Articulated commissure valve stents and methods

ABSTRACT

A support structure includes strut members interconnected by rotatable joints to form a series of linked scissor mechanisms. The structure can be remotely actuated to compress or expand its shape by adjusting the scissor joints within a range of motion. In particular, the support structure can be repositioned within the body lumen or retrieved from the lumen. The support structure can be employed to introduce and support a prosthetic valve within a body lumen.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application Ser.No. 61/780,670, filed Mar. 13, 2013, and titled “ARTICULATED COMMISSUREVALVE STENTS AND METHODS,” the content of which is hereby incorporatedin its entirety.

BACKGROUND

Endoluminal stents can be implanted in a vessel or tract of a patient tohelp maintain an open lumen. The stents can also be used as a frame tosupport a prosthetic device or to deliver a therapeutic agent. Stentscan be implanted by either an open operative procedure or a closedoperative procedure. When an option exists, the less invasive closedprocedure is generally preferred because the stent can be guided througha body lumen, such as the femoral artery, to its desired location.

Closed procedures typically use one of two techniques. One closedprocedure employs balloon catheterization where an expandable stentencloses an inflatable balloon. In this procedure, the stent isimplanted by inflating the balloon, which causes the stent to expand.The actual positioning of the stent cannot be determined until after theballoon is deflated and, if there is a misplacement of the stent, theprocess cannot be reversed to reposition the stent.

The other closed procedure employs a compressed stent enclosed by aremovable sheath. In this procedure, a stent made from a shape memoryalloy, such as Nitinol, is held in a compressed state by a sheath. Thestent is implanted by withdrawing the sheath, causing the stent toexpand to its nominal shape. Again, if there is a misplacement of thestent, the process cannot be reversed to reposition the stent.

Positioning errors are particularly dangerous when the stent is used tosupport a cardiac valve. Serious complications and patient deaths haveoccurred due to malpositioning of the valve at the implant site in thebody, using the available stent-mounted valves. Malpositioning of thevalve has resulted in massive paravalvular leakage, device migration,and coronary artery obstruction. The majority of these complicationswere unavoidable, but detected at the time of the procedure. However,due to inability to reposition or retrieve the device, these problemswere impossible to reverse or mitigate during the procedure.

SUMMARY

An endoluminal support structure or stent in accordance with certainembodiments of the invention solves certain deficiencies found in theprior art. In particular, the support structure can be repositionedwithin the body lumen or retrieved from the lumen.

A particular embodiment of the invention includes a support apparatusimplantable within a biological lumen. The support apparatus can includea plurality of elongated strut members interlinked by a plurality ofrotatable joints, wherein the rotatable joints can cooperate with thestent members to adjustably define a shaped structure between acompressed orientation and an expanded orientation.

More particularly, the shaped structure can be one of a cylindrical, aconical, or an hourglass shape. A rotatable joint can form a scissormechanism with a first strut member and a second strut member.Furthermore, the strut members can be arranged as a series of linkedscissor mechanisms. The apparatus can further include an actuationmechanism to urge the rotatable joints within a range of motion.

The apparatus can also include a prosthetic valve coupled to the shapedstructure.

Another particular embodiment of the invention can include a medicalstent implantable within a biological lumen. The medical stent caninclude a plurality of elongated strut members, including a first strutmember and a second strut member, and a rotatable joint connecting thefirst strut member and the second strut member.

In particular, the rotatable joint can form a scissor mechanism with thefirst strut member and the second strut member. The rotatable joint canbisect the first strut member and the second strut member. The rotatablejoint can interconnect a first end of the first strut member with afirst end of the second strut member.

The plurality of strut members can be arranged as a series of linkedscissor mechanisms. The strut members can also be non-linear. The strutmembers can be arranged to form one of a cylindrical, a conical, or anhourglass shape.

The stent can further include an adjustment mechanism to exerting aforce to urge the strut members about the rotatable joint within a rangeof motion.

The stent can include a prosthetic valve coupled to the strut members.

Specific embodiments of the invention can include prosthetic valves thatare rotatable or conventional.

A rotatable prosthetic valve can include a first structural membercoupled to the strut members, a second structural member rotatablerelative to the first structural member, and a plurality of pliablevalve members connecting the first structural member with the secondstructural member such that rotation of the second structural memberrelative to the first structural member can urge the valve membersbetween an open and a closed state. In particular, the rotation of thesecond structural member can be responsive to the natural flow of abiological fluid.

A conventional prosthetic valve can include a plurality of pliable valveleaflets having commissures at the intersection of two strut members.The prosthetic valve can further include a skirt material coupled to thestrut members.

These structures can also be interconnected in various combinations.

A particular advantage of a support structure in accordance withembodiments of the invention is that it enables a prosthetic valve to bereadily retrieved and repositioned in the body. If following deployment,the valve is malpositioned or deemed dysfunctional, the supportstructure allows the valve to be readily repositioned and re-deployed ata new implant site, or removed from the body entirely. This feature ofthe device can prevent serious complications and save lives by enablingthe repair of mal-positioned devices in the body.

A particular embodiment of the invention comprises a biocompatiblearticulated support structure, comprising a tubular support body with aproximal opening, and a distal opening, with a lumen and a longitudinalaxis between the proximal and distal openings, wherein the tubular bodycomprises a plurality of discrete struts coupled by a plurality ofrotatable articulations, each articulation comprising an axis ofrotation with a radial orientation, and wherein the plurality ofrotatable articulations comprise a set of proximal rotatablearticulations configured to reside in a proximal plane with the proximalopening, a set of distal rotatable articulations configured to reside ina distal plane with the distal opening, a first set of middle rotatablearticulations, located between the proximal plane and the distal plane,and at least one commissural point articulation distal to the distalplane, and wherein the plurality of discrete inner struts, the pluralityof discrete outer struts and the articulations therebetweenintrinsically provide a self-expansion force. The support structure mayhave at least one commissural point articulation is linked by at leasttwo of the plurality of discrete struts to two commissural basearticulations. The two commissural base articulations may be located ator proximal to the distal plane. When the tubular support body is in anexpanded state, the first set of middle rotatable articulations, may belocated closer to the proximal plane than the distal plane. Theplurality of discrete struts may comprise a plurality of inner struts, aplurality of outer struts, and at least a pair of an inner commissuralstrut and an outer commissural strut. Each of the plurality of innerstruts may be coupled to two of the plurality of outer struts, andeither a third strut from the plurality of outer struts or one of the atleast one outer commissural struts. Each of the plurality of outerstruts is coupled to two of the plurality of inner struts, and either athird strut from the plurality of inner struts or one of the at leastone inner commissural struts. When the tubular support body is in anexpanded state, the average angle of the at least one commissural pointarticulation may be less than the average angle of the set of distalrotatable articulations. Each of the plurality of inner struts that isnot coupled to a commissural strut and each of the plurality of outerstruts that is not coupled to a commissural strut has a first length,and wherein each of the plurality of inner struts that is coupled to acommissural strut and each of the plurality of outer struts coupled to acommissural strut has a second length, and the second length may bedifferent from the first length, or the second length may shorter thanthe first length. When the tubular support body is in the expandedstate, a distance between the at least one commissural pointarticulation and the distal plane may be at least 20% of a longitudinaldistance between the proximal and distal planes. The support structuremay further comprise an expandable hourglass securing body comprising aproximal opening, and a distal opening, with a lumen and a longitudinalaxis between the proximal and distal openings, and wherein the tubularsupport body may be configured to reside within the lumen of theexpandable hourglass securing body. The expandable hourglass structuremay comprise a distal tapered section, a proximal tapered section, and anarrow section therebetween, and wherein the tubular support body may besecured to the narrow section. The expandable hourglass securing bodymay comprise a plurality of discrete non-linear struts interconnected byrotatable articulations with a rotation of axis in a radial orientation.The support structure may further comprise at least one locking ringsecured to at least one of the distal tapered section and the proximaltapered section. The at least one locking ring may be located within thelumen of the expandable securing body. The at least one locking ring maycomprise a plurality of inner struts and a plurality of outer strutsinterconnected by rotatable articulations with a rotation of axis in aradial orientation.

A particular embodiment of the invention comprises a biocompatiblearticulated support structure, comprising a tubular structure comprisinga central lumen, a central axis, a plurality of discrete inner struts,and a plurality of discrete outer struts, wherein each of the pluralityof discrete inner struts and the plurality of discrete outer strutscomprises first end, a second end, and a net length therebetween, andwherein each of the plurality of discrete inner struts comprisesarticulations with at least two different discrete outer struts of theplurality of discrete outer struts, and wherein each of the plurality ofdiscrete outer struts comprises articulations with at least twodifferent discrete inner struts of the plurality of discrete innerstruts, and wherein no discrete inner strut of the plurality of discreteinner struts comprises articulations with any other discrete inner strutof the plurality of discrete inner struts, and wherein no discrete outerstrut of the plurality of discrete outer struts comprises articulationswith any other discrete outer strut of the plurality of discrete outerstruts, and wherein at least one strut from either the plurality ofdiscrete inner struts or the plurality of discrete outer strutscomprises first end, a second end, and a net length therebetween, andwherein the first end of the at least one strut is spaced apart from aclosest articulation by about at least 25% of the net length of thatstrut. The first end of each of the plurality of discrete outer strutsmay be spaced apart from a closest articulation by about at least 25% ofits net length. The second end of each of the plurality of discreteouter struts may be spaced apart from a closest articulation by about atleast 25% of its net length. The first end of each of the plurality ofdiscrete inner struts may be spaced apart from a closest articulation byabout at least 25% of its net length. The second end of each of theplurality of discrete inner struts may be spaced apart from a closestarticulation by about at least 25% of its net length.

A particular embodiment of the invention comprises a biocompatiblearticulated support structure, comprising a tubular structure comprisinga central lumen, a central axis, a plurality of discrete inner struts, aplurality of discrete outer struts, and at least one bow strut, whereineach of the plurality of discrete inner struts, the plurality ofdiscrete outer struts and the at least one bow strut comprises firstend, a second end, and a net length therebetween, and wherein each ofthe plurality of discrete inner struts comprises articulations with atleast two different discrete outer struts of the plurality of discreteouter struts, and wherein each of the plurality of discrete outer strutscomprises articulations with at least two different discrete innerstruts of the plurality of discrete inner struts, and wherein nodiscrete inner strut of the plurality of discrete inner struts comprisesarticulations with any other discrete inner strut of the plurality ofdiscrete inner struts, and wherein no discrete outer strut of theplurality of discrete outer struts comprises articulations with anyother discrete outer strut of the plurality of discrete outer struts,and wherein the at least one bow strut comprises a first articulationwith a first strut selected from either the plurality of discrete innerstruts and the plurality of discrete outer struts, and a secondarticulation with a second strut selected from the same plurality ofdiscrete inner struts or plurality of discrete outer struts. The firststrut and the second struts may be directly adjacent struts. The atleast one bow strut may be an inner bow strut wherein the first andsecond struts may be selected from the plurality of discrete innerstruts. The at least one bow strut may be a plurality of inner bowstruts. The at least one bow strut may be an outer bow strut wherein thefirst and second struts may be selected from the plurality of discreteouter struts. The at least one bow strut may be a plurality of outer bowstruts. The support structure may further comprise a secondary structurelocated between the plurality of outer bow struts and the plurality ofdiscrete outer struts. The secondary structure may be a circumferentialtubular balloon.

A particular embodiment of the invention comprises a biocompatiblearticulated structure, comprising a tubular structure comprising acentral lumen, a central axis, a plurality of discrete inner struts, aplurality of discrete outer struts, and at least two radial struts,wherein each of the plurality of discrete inner struts and the pluralityof discrete outer struts comprises first end, a second end, and a netlength therebetween, and wherein each of the at least two radial strutscomprises an outer end, an inner end and a net length therebetween,wherein each outer end is coupled to at least one strut selected fromthe plurality of discrete inner struts and the plurality of discreteouter struts, and wherein the inner ends of the at least two radialstruts are coupled together, and wherein each of the plurality ofdiscrete inner struts comprises articulations with at least threedifferent discrete outer struts of the plurality of discrete outerstruts, and wherein each of the plurality of discrete outer strutscomprises articulations with at least three different discrete innerstruts of the plurality of discrete inner struts, and wherein nodiscrete inner strut of the plurality of discrete inner struts comprisesarticulations with any other discrete inner strut of the plurality ofdiscrete inner struts, and wherein no discrete outer strut of theplurality of discrete outer struts comprises articulations with anyother discrete outer strut of the plurality of discrete outer struts.The inner ends of the at least two radial struts may be coupled atcentrally aligned coupling apertures. The inner ends of the at least tworadial struts may be coupled at coupling apertures using a loop couplingstructure. The at least two radial struts may comprise a first pluralityof radial struts and a second plurality of radial struts, wherein eachouter end of the first plurality of radial struts may be coupled to thefirst ends of at least one strut selected from the plurality of discreteinner struts and the plurality of discrete outer struts, and whereineach outer end of the second plurality of radial struts may be coupledto the second ends of at least one strut selected from the plurality ofdiscrete inner struts and the plurality of discrete outer struts. Theinner ends of the first plurality of radial struts may be coupledtogether and the inner ends of the second plurality of radial struts maybe coupled together. The inner ends of the first plurality of radialstruts may be attached to a first deployment structure and the innerends of the second plurality of radial struts may be attached to asecond deployment structure. The inner ends of the first plurality ofradial struts may be attached to a first region of a deploymentstructure and the inner ends of the second plurality of radial strutsmay be attached to a second region of the deployment structure. Thedeployment structure may be a screw drive mechanism. The structure mayfurther comprise a delivery catheter permanently attached to the tubularstructure. The delivery catheter may comprise a plurality of wireselectrically coupled to the tubular structure.

A particular embodiment of the invention comprises a biocompatiblearticulated structure, comprising a tubular structure comprising acentral lumen, a central axis, a plurality of discrete inner struts, anda plurality of discrete outer struts, wherein each of the plurality ofdiscrete inner struts and the plurality of discrete outer strutscomprises first end, a second end, and a net length therebetween,wherein each of the plurality of discrete inner struts comprisesarticulations with at least four different discrete outer struts of theplurality of discrete outer struts, and wherein each of the plurality ofdiscrete outer struts comprises articulations with at least fourdifferent discrete inner struts of the plurality of discrete innerstruts, and wherein no discrete inner strut of the plurality of discreteinner struts comprises articulations with any other discrete inner strutof the plurality of discrete inner struts, and wherein no discrete outerstrut of the plurality of discrete outer struts comprises articulationswith any other discrete outer strut of the plurality of discrete outerstruts, and wherein at least one strut from either the plurality ofdiscrete inner struts or the plurality of discrete outer strutscomprises first end, a second end, and a net length therebetween; andwherein the plurality of discrete inner struts, the plurality ofdiscrete outer struts and the articulations therebetween intrinsicallyprovide a self-expansion force. The tubular structure may comprise anintrinsically stable non-expanding collapsed state. The plurality ofdiscrete inner struts and the plurality of discrete outer struts may beconfigured to form a first set of cells aligned along a first perimeterof the tubular structure and a second set of cells directly adjacent tothe first set of cells and aligned along a second perimeter of thetubular structure. The plurality of discrete inner struts comprisesarticulations with at least five different discrete outer struts of theplurality of discrete outer struts, wherein each of the plurality ofdiscrete outer struts may comprise articulations with at least fivedifferent discrete inner struts of the plurality of discrete innerstruts, and wherein the plurality of discrete inner struts and theplurality of discrete outer struts may be further configured to form athird set of cells directly adjacent to the second set of cells andaligned along a third perimeter of the tubular structure.

A particular embodiment of the invention comprises a biocompatiblearticulated structure comprising a tubular structure comprising acentral lumen, a central axis, a plurality of discrete inner struts, aplurality of discrete outer struts, and a plurality of discretecommissure struts, wherein each of the plurality of discrete innerstruts and the plurality of discrete outer struts comprises a first end,a second end, and a net length therebetween, and wherein each of theplurality of discrete inner struts comprises articulations with at leastthree different discrete outer or commissure struts of the pluralitiesof discrete outer and commissure struts, and wherein each of theplurality of discrete outer struts comprises articulations with at leastthree different discrete inner or commissure struts of the pluralitiesof discrete inner and commissure struts, and wherein each of theplurality of discrete commissure struts comprises articulations with onediscrete outer or inner strut of the pluralities of discrete outer andinner struts and with one other discrete commissure strut of theplurality of discrete commissure struts, and wherein no discrete innerstrut of the plurality of inner struts comprises articulations with anyother discrete inner strut of the plurality of discrete inner struts;and wherein no discrete outer strut of the plurality of discrete outerstruts comprises articulations with any other discrete outer strut ofthe plurality of discrete outer struts.

A particular embodiment of the invention comprises a biocompatiblearticulated support structure, comprising an hourglass structurecomprising a central lumen, a central axis, a plurality of discreteinner struts, and a plurality of discrete outer struts, wherein each ofthe plurality of discrete inner struts and the plurality of discreteouter struts comprises a first end, a second end, and a net lengththerebetween; and wherein each of the plurality of discrete inner strutsand the plurality of discrete outer struts has a helical configurationwith the helical axis aligned with the central axis of the structure;and wherein each of the plurality of discrete inner struts comprises twoarticulations with a single discrete outer strut of the plurality ofdiscrete outer struts, and at least one articulation with a differentdiscrete outer strut of the plurality of discrete outer struts; andwherein each of the plurality of discrete outer struts comprises twoarticulations with a single discrete inner strut of the plurality ofdiscrete inner struts, and at least one articulation with a differentdiscrete inner strut of the plurality of discrete inner struts; andwherein no discrete inner strut of the plurality of inner strutscomprises articulations with any other discrete inner strut of theplurality of discrete inner struts; and wherein no discrete outer strutof the plurality of discrete outer struts comprises articulations withany other discrete outer strut of the plurality of discrete outerstruts; and wherein the diameter of the support structure at either endof the central axis is greater than the diameter of the supportstructure at the midpoint of the central axis.

A particular embodiment of the invention comprises a biocompatiblearticulated support structure, comprising a tubular structure comprisinga central lumen, a central axis, a plurality of discrete inner struts,and a plurality of discrete outer struts, wherein each of the pluralityof discrete inner struts and the plurality of discrete outer strutscomprises a first end, a second end, and a net length therebetween,wherein each of the plurality of discrete inner struts comprisesarticulations with at least three different discrete outer struts of theplurality of discrete outer struts, and wherein each of the plurality ofdiscrete outer struts comprises articulations with at least threedifferent discrete inner struts of the plurality of discrete innerstruts, and wherein no discrete inner strut of the plurality of innerstruts comprises articulations with any other discrete inner strut ofthe plurality of discrete inner struts, and wherein no discrete outerstrut of the plurality of discrete outer struts comprises articulationswith any other discrete outer strut of the plurality of discrete outerstruts, and wherein the support structure is in an unstressed state whenin a fully expanded configuration.

A particular embodiment of the invention comprises a biocompatiblearticulated support structure, comprising a valve structure, comprisinga tubular structure comprising a central lumen, a central axis, aplurality of discrete inner struts, a plurality of discrete outerstruts, and a plurality of discrete commissure struts, wherein each ofthe plurality of discrete inner struts and the plurality of discreteouter struts comprises a first end, a second end, and a net lengththerebetween, wherein each of the plurality of discrete inner strutscomprises articulations with at least three different discrete outer orcommissure struts of the pluralities of discrete outer and commissurestruts, and wherein each of the plurality of discrete outer strutscomprises articulations with at least three different discrete inner orcommissure struts of the pluralities of discrete inner and commissurestruts, and wherein each of the plurality of discrete commissure strutscomprises articulations with one discrete outer or inner strut of thepluralities of discrete outer and inner struts and with one otherdiscrete commissure strut of the plurality of discrete commissurestruts, and wherein no discrete inner strut of the plurality of innerstruts comprises articulations with any other discrete inner strut ofthe plurality of discrete inner struts, and wherein no discrete outerstrut of the plurality of discrete outer struts comprises articulationswith any other discrete outer strut of the plurality of discrete outerstruts, and a fixation structure, comprising an hourglass structurecomprising a central lumen, a central axis, a plurality of discreteinner struts, and a plurality of discrete outer struts, wherein each ofthe plurality of discrete inner struts and the plurality of discreteouter struts comprises a first end, a second end, and a net lengththerebetween, and wherein each of the plurality of discrete inner strutsand the plurality of discrete outer struts has a helical configurationwith the helical axis aligned with the central axis of the structure,and wherein each of the plurality of discrete inner struts comprises twoarticulations with a single discrete outer strut of the plurality ofdiscrete outer struts, and at least one articulation with a differentdiscrete outer strut of the plurality of discrete outer struts, andwherein each of the plurality of discrete outer struts comprises twoarticulations with a single discrete inner strut of the plurality ofdiscrete inner struts, and at least one articulation with a differentdiscrete inner strut of the plurality of discrete inner struts, andwherein no discrete inner strut of the plurality of inner strutscomprises articulations with any other discrete inner strut of theplurality of discrete inner struts, and wherein no discrete outer strutof the plurality of discrete outer struts comprises articulations withany other discrete outer strut of the plurality of discrete outerstruts, and wherein the diameter of the support structure at either endof the central axis is greater than the diameter of the supportstructure at the midpoint of the central axis, at least two locking ringstructures, comprising a tubular structure comprising a central lumen, acentral axis, a plurality of discrete inner struts, a plurality ofdiscrete outer struts, wherein each of the plurality of discrete innerstruts and the plurality of discrete outer struts comprises a first end,a second end, and a net length therebetween, wherein each of theplurality of discrete inner struts comprises articulations with at leastthree different discrete outer struts of the plurality of discrete outerstruts, and wherein each of the plurality of discrete outer strutscomprises articulations with at least three different discrete innerstruts of the plurality of discrete inner struts, and wherein nodiscrete inner strut of the plurality of inner struts comprisesarticulations with any other discrete inner strut of the plurality ofdiscrete inner struts, and wherein no discrete outer strut of theplurality of discrete outer struts comprises articulations with anyother discrete outer strut of the plurality of discrete outer struts,and wherein the support structure is in an unstressed state when in afully expanded configuration, and wherein the central axes of the valvestructure, fixation structure, and two locking ring structures arealigned, and wherein the valve structure is attached to at least onepoint to the fixation structure, and wherein each of the two lockingring structures is attached to at least one point to the fixationstructure.

A particular embodiment of the invention comprises a biocompatiblesupport structure delivery system, comprising an expandable supportstructure having proximal and distal ends, at least one ring attached tothe proximal end of the support structure, at least one ring attached tothe distal end of the support structure, wherein the at least one ringsare attached to the support structure by loops, such that the rings canrotate freely within the loops, and wherein the rings are configured toattach to a control catheter assembly.

A particular embodiment of the invention comprises a method forimplanting a biocompatible support structure, wherein the biocompatiblesupport structure comprises an expandable support structure havingproximal and distal ends, at least one ring attached to the proximal endof the support structure, and at least one ring attached to the distalend of the support structure, and wherein the rings are configured toattach to a control catheter assembly, comprising connecting the atleast one ring attached to the proximal end of the support structure tothe control catheter assembly, connecting the at least one ring attachedto the distal end of the support structure to the control catheterassembly, using the control catheter assembly to move the distal end ofthe support structure toward the proximal end of the support structure,wherein moving the distal end of the support structure toward theproximal end of the support structure causes the support structure toexpand radially, and detaching the at least one ring attached to theproximal end of the support structure and the at least one ring attachedto the distal end of the support structure from the control catheterassembly to release the support structure.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, features and advantages of theinvention will be apparent from the following more particulardescription of particular embodiments of the invention, as illustratedin the accompanying drawings in which like reference characters refer tothe same parts throughout the different views. The drawings are notnecessarily to scale, emphasis instead being placed upon illustratingthe principles of the invention.

FIG. 1 is a perspective view of a particular endoluminal supportstructure.

FIG. 2 is a perspective view of a four strut section of the stent ofFIG. 1.

FIG. 3 is a perspective view of a compressed support structure of FIG.1.

FIG. 4 is a perspective view of the support structure of FIG. 1 in afully expanded state.

FIG. 5 is a perspective view of the support structure of FIG. 2 having aparticular actuator mechanism.

FIG. 6 is a perspective view of the support structure of FIG. 2 havinganother particular actuator mechanism.

FIG. 7 is a perspective view of a particular support structure andcontrol catheter assembly usable with the actuator mechanisms of FIGS. 5and 6.

FIG. 8 is a perspective view of a particular rotating prosthetic valveassembly.

FIG. 9 is a perspective view of the valve assembly of FIG. 8 while beingclosed.

FIG. 10 is a perspective view of the valve assembly of FIG. 8 oncecompletely closed.

FIG. 11 is a perspective view of the valve of FIGS. 8-10 in combinationwith the support structure of FIG. 1.

FIG. 12 is a perspective view of the valve of FIG. 11 in the openposition.

FIG. 13 is a perspective view of a traditional tissue valve mounted tothe support structure of FIG. 1.

FIG. 14 is a perspective view of the valve structure of FIG. 13 having afull inner skirt.

FIG. 15 is a perspective view of the valve structure of FIG. 13 having afull outer skirt.

FIG. 16 is a perspective view of the arrangement of strut members in aconical-shaped support structure configuration.

FIG. 17 is a perspective view of an hourglass-shaped support structureconfiguration.

FIGS. 18A and 18B are perspective and side elevational views,respectively, of one embodiment of an articulated support structurecomprising strut extension segments.

FIGS. 19A and 19B are perspective and side elevational views,respectively, of one embodiment of an articulated support structurecomprising inner and outer bow struts.

FIG. 20 depicts a perspective view of an embodiment of a self-expandingarticulated structure comprising a multi-level configuration.

FIG. 21 depicts a perspective view of an embodiment of an articulatedsupport structure comprising centrally attached radial struts.

FIGS. 22A and 22B are schematic superior views of alternate embodimentsof interconnection configurations of the centrally attached radialstruts in FIG. 21.

FIG. 23 is a perspective view of an embodiment of an articulated supportstructure comprising dual deployment wires.

FIG. 24 is a perspective view of an embodiment of an articulated supportstructure comprising a deployment shaft.

FIG. 25 is a perspective view of a particular endoluminal supportstructure.

FIG. 26 is a perspective view of a six strut section of the structure ofFIG. 25.

FIG. 27A is a perspective view of another embodiments of an endoluminalsupport structure.

FIG. 27B is the structure of FIG. 27A with a tissue valve mounted to thestructure in combination with the support structure in FIG. 33.

FIG. 28 is a schematic perspective view of a traditional tissue valvemounted to the structure of FIG. 25.

FIG. 29A depicts an hourglass securing support structure with attacheddeployment structure.

FIG. 29B depicts another embodiment of an hourglass securing supportstructure with attached locking rings and deployment structure.

FIG. 30 illustrates a perspective view of a particular endoluminalsupport structure.

FIG. 31A is a combined structure with the hourglass support structure ofFIG. 29A, support structure of FIG. 27A, and support structures of FIG.1, shown in an expanded state.

FIG. 31B is an axial view of the structure of FIG. 31A.

FIGS. 31C and 31D are various side perspective views the combinedstructure of FIG. 31A deployed through an opening.

FIG. 31E is an axial view of the combination of FIG. 31A deployedthrough the opening.

FIGS. 31F and 31G are side perspective views of the combined structurein FIG. 31A coupled to a control catheter assembly, in an expandedstate.

FIG. 31H is an axial view of the combined structure in FIGS. 31F and31G.

FIG. 31I is the combination of FIG. 31A, with control catheter assembly,in a collapsed state.

FIG. 32 is a side view of a control catheter assembly.

FIG. 33 is a side view of an embodiment of an hourglass securing supportstructure.

FIG. 34 is a schematic illustration of a valve leaflet.

FIGS. 35A to 35C depict various embodiments of support structures withskirts.

FIGS. 35D and 35E are ventricular and atrial views of a supportstructure with a skirt implanted in a cadaver heart at the mitral valveposition, respectively.

DETAILED DESCRIPTION

Particular embodiments of the invention include endoluminal supportstructures (stents) and prosthetic valves.

FIG. 1 is a perspective view of a particular endoluminal supportstructure. As shown, the support structure 10 is a medical stent thatincludes a plurality of longitudinal strut members 11 interconnected bya plurality of rotatable joints 15. In particular, the swivel joints 15may allow the interconnected strut members 11 to rotate relative to eachother. The rotatable joints may be able to be rotated about an axis ofrotation, and/or may be swivelable. As shown, there are eighteen struts11.

The strut members 11 may be fabricated from a rigid or semi-rigidbiocompatible material, such as plastics or other polymers and metalalloys, including stainless steel, tantalum, titanium, nickel-titanium(e.g. Nitinol), and cobalt-chromium (e.g. ELGILOY). The dimensions ofeach strut can be chosen in accordance with its desired use. In aparticular embodiment, each strut member may be made from stainlesssteel, which is about 0.001-0.100 inch thick. More particularly, eachstrut can be about 0.01 inch thick 300 series stainless steel. Inanother embodiment, each strut member can be made from cobalt-chromium(e.g. ELGILOY). While all struts 11 are shown as being of uniformthickness, the thickness of a strut can vary across a strut, such as agradual increase or decrease in thickness along the length of a strut.Furthermore, individual struts can differ in thickness from otherindividual struts in the same support structure. In a particularembodiment, each strut member may be about 0.01-0.25 inches wide andabout 0.25-3 inches long. More particularly, each strut can be about0.06 inches wide and about 0.5 inches long. As shown, each strut member11 is bar shaped and has a front surface 11 f and a back surface 11 b.The strut members can however be of different geometries. For example,instead of a uniform width, a strut can vary in width along its length.Furthermore, an individual strut can have a different width than anotherstrut in the same support structure. Similarly, the strut lengths canvary from strut to strut within the same support structure. Theparticular dimensions can be chosen based on the implant site.

Furthermore, the struts can be non-flat structures. In particular, thestruts can include a curvature, such as in a concave or convex manner inrelationship to the inner diameter of the stent structure. The strutscan also be twisted. The nonflatness or flatness of the struts can be aproperty of the material from which they are constructed. For example,the struts can exhibit shape-memory or heat-responsive changes in shapeto the struts during various states. Such states can be defined by thestent in the compressed or expanded configuration.

Furthermore, the strut members 11 can have a smooth or rough surfacetexture. In particular, a pitted surface can provide tensile strength tothe struts. In addition, roughness or pitting can provide additionalfriction to help secure the support structure at the implant site andencourage irregular encapsulation of the support structure 10 by tissuegrowth to further stabilize the support structure 10 at the implant siteover time.

In certain instances, the stent could be comprised of struts that aremultiple members stacked upon one another. Within the same stent, somestruts could include elongated members stacked upon one another in amulti-ply configuration, and other struts could be one-ply, composed ofsingle-thickness members. Within a single strut, there can be areas ofone-ply and multi-ply layering of the members.

Each strut member 11 may also include a plurality of orifices 13 spacedalong the length of the strut member 11. On the front surface 11 f, theorifices may be countersunk 17 to receive the head of a fastener. In aparticular embodiment, there are thirteen equally spaced orifices 13along the length of each strut member 11, but more or less orifices canbe used. The orifices 13 are shown as being of uniform diameter anduniform spacing along the strut member 11, but neither is required.

The strut members 11 can be arranged as a chain of four-bar linkages.The strut members 11 may be interconnected by pivot fasteners 25, suchas rivets or capped pin, extending through aligned orifices 13, whichmay or may not be configured to permit rotating or tilting movement ofthe strut. It should be understood that other rotatable fasteners 25 canbe employed such as screws, bolts, ball-in-socket structures, nails, oreyelets, and that the fasteners can be integrally formed in the struts11 such as a peened semi-sphere interacting with an indentation ororifice, or a male-female coupling. In addition to receiving a fastener,the orifices 13 also provide an additional pathway for tissuegrowth-over to stabilize and encapsulate the support structure 10 overtime.

FIG. 2 is a perspective view of a four strut section of the stent ofFIG. 1. As shown, two outer strut members 11-1, 11-3 overlap two innerstrut members 11-2, 11-4, with their back surfaces in communication witheach other.

In particular, the first strut member 11-1 may be rotatably connected tothe second strut member 11-2 by a middle rotatable joint 15-1 using arivet 25-1, which utilizes orifices 13 that bisect the strut members11-1, 11-2. Similarly, the third strut member 11-3 may be rotatablyconnected to bisect the fourth strut member 11-4 by a middle rotatablejoint 15-7 using a rivet 25-7. It should be understood that the middlerotatable joints 15-1, 15-7 can function as a scissor joint in a scissorlinkage or mechanism. As shown, the resulting scissor arms are of equallength. It should also be understood that the middle joint 15-1, 15-7need not bisect the joined strut members, but can instead utilizeorifices 13 offset from the longitudinal centers of the strut membersresulting in unequal scissor arm lengths.

In addition to the middle scissor joint 15-1, the second strut member11-2 is rotatably connected to the third strut member 11-3 by a distalanchor rotatable joint 15-5, located near the distal ends of the strutmembers 11-2, 11-3. Similarly, the first strut member 11-1 is rotatablyconnected to the fourth strut member 11-4 by a proximal anchor rotatablejoint 15-3, located near the proximal ends of the strut members 11-1,11-4. To reduce stresses on the anchor rivets 25-3, 25-5, the distal andproximal ends of the struts 11 can be curved or twisted to provide aflush interface between the joined struts. As a result of theserotatable connections, the linkage can be reversibly expanded andcompressed. When the linkage is laterally compressed, the two strutmembers 11-4 and 11-2 move to be directly adjacent to each other, andthe two strut members 11-3 and 11-1 move to be directly adjacent to eachother, such that center diamond-shaped opening is substantially closed.When the linkage is laterally expanded, the center diamond-shapedopening is widened.

As can be seen, the support structure 10 (FIG. 1) may be fabricated bylinking together a serial chain of scissor mechanisms. The chain maythen be wrapped to join the last scissor mechanism with the firstscissor mechanism in the chain. By actuating the linkage the links canbe opened or closed, which results in expanding or compressing the stent10 (FIG. 1). FIG. 1 shows a serial chain of scissor mechanisms such thatthere are eighteen struts 11, but other numbers of struts 11 can beused. FIG. 30, for example, shows a support structure 3010 with a serialchain of scissor mechanisms having twelve struts 11. As shown in FIG.30, the struts 11 need not have orifices 13. In other variations,support structures having twelve struts 11 as in FIG. 30 may haveorifices. This variation of support structure 3010 having twelve strutswith orifices is shown as part of the combination structure in FIGS.31A-I. FIG. 30 also shows struts 11 having a curvature, as describedabove. Support structure 3010, or support structures having othernumbers or configurations of struts, can be reversibly expanded,reversibly compressed, fully expanded to form a ring, implanted, usedwith an actuator mechanism and control catheter assembly, and/or used tosupport a prosthetic valve in the same manner as support structure 10,described in detail below.

Returning to FIG. 1, by utilizing the rotatable joints 15, the diameterof the stent can be compressed for insertion through a biological lumen,such as an artery, to a selected position. The stent can then beexpanded to secure the stent at the selected location within the lumen.Furthermore, after being expanded, the stent can be recompressed forremoval from the body or for repositioning within the lumen.

FIG. 3 is a perspective view of a compressed support structure ofFIG. 1. When compressed, the stent 10 is at its maximum length andminimum diameter. The maximum length may be limited by the length of thestrut members, which in a particular embodiment may be 15 mm. Theminimum diameter may be limited by the width of the strut members, whichin a particular embodiment may be about 0.052 inch. In compressed asshown in FIG. 3, the support structure is highly compact. However, thesupport structure may retain an open lumen through it while in thecompressed state.

FIG. 4 is a perspective view of the support structure of FIG. 1 in afully expanded state. As shown, the fully expanded support structure 10forms a ring. Once in a fully expanded state, support structure 10 mayenter a locked state such that radial inward pressure does not cause thesupport structure to re-compress and the support structure 10 is in anunstressed state. The ring formed can be used as an annuloplasty ring.In particular, if one end of the stent circumference is attached totissue, the compression of the stent may enable the tissue to cinch.Because the stent may have the ability to have an incremental andreversible compression or expansion, the device could be used to providean individualized cinching of the tissue to increase the competency of aheart valve. This could be a useful treatment for mitral valve diseases,such as mitral regurgitation or mitral valve prolapse.

While the support structure 10 may be able to be implanted in a patientduring an open operative procedure, a closed procedure may also bedesirable. As such, the support structure 10 may include an actuationmechanism to allow a surgeon to expand or compress the support structurefrom a location remote from the implant site. Due to the properties of ascissor linkage wrapped into a cylinder (FIG. 1), actuation mechanismscan exert force to expand the stent diameter by either increasing thedistance between neighboring scissor joints, and decreasing the distancebetween the anchor joints.

FIG. 5 is a perspective view of the support structure of FIG. 2 having aparticular actuator mechanism. As shown, the actuator mechanism 30includes a dual-threaded rod 32 positioned on the inside of the supportstructure 10 (FIG. 1). It should be understood, however, that theactuator mechanism 30 can instead be positioned on the outside of thesupport structure 10. Whether positioned on the inside or outside, theactuator mechanism 30 may operate in the same way. The rod may includeright-hand threads 34R on its proximal end and left-hand threads 34L onits distal end. The rod 32 may be mounted the anchor points 15-3, 15-5using a pair of threaded low-profile support mounts 35-3, 35-5. Each endof the rod 32 may be terminated by a hex head 37-3, 37-5 for receiving ahex driver (not shown). As should be understood, rotating the rod 32 inone direction may urge the anchor points 25-3, 25-5 outwardly tocompress the linkages while rotating the rod 32 in the oppositedirection may urge the anchor points 25-3, 25-5 inwardly to expand thelinkages.

FIG. 6 is a perspective view of the support structure of FIG. 2 havinganother particular actuator mechanism. As shown, the actuator mechanism30′ includes a single-threaded rod 32′positioned on the inside of thesupport structure 10 (FIG. 1). The rod 32′ may include threads 34′ onone of its ends. The rod 32′ may be mounted to low profile anchor points15-3, 15-5 using a pair of support mounts 35′-3, 35′-5, one of which isthreaded to mate with the rod threads 34′. The unthreaded end of the rod32′ may include a retaining stop 39′ that bears against the supportmount 35′-5 to compress the support structure. Each end of the rod 32′can be terminated by a hex head 37′-3, 37′-5 for receiving a hex driver(not shown). Again, rotating the rod 32′ in one direction may urge theanchor points 25-3, 25-5 outwardly to compress the linkages whilerotating the rod 32′ in the opposite direction may urge the anchorpoints 25-3, 25-5 inwardly to expand the linkages.

In addition, because the struts overlap, a ratcheting mechanism can beincorporated to be utilized during the sliding of one strut relative tothe other. For example, the stent could lock at incremental diametersdue to the interaction of features that are an integral part of eachstrut. An example of such features would be a male component (e.g.bumps) on one strut surface which mates with the female component (e.g.holes) on the surface of the neighboring strut surface, as the twostruts slide pass one another. Such structures could be fabricated tohave an orientation, such that they incrementally lock the stent in theexpanded configuration as the stent is expanded. Such a stent could beexpanded using a conventional balloon or other actuation mechanismdescribed in this application.

Because the support structure 10 of FIGS. 5 and 6 may be configured tobe implanted during a closed surgical procedure, the actuator mechanismmay be able to be controlled remotely by a surgeon. In a typicalprocedure, the support structure 10 may be implanted through a bodylumen, such as the femoral artery using a tethered endoluminal catheter.As such, the actuator mechanism 30 may be able to be controlled via thecatheter.

FIG. 7 is a perspective view of a particular support structure andcontrol catheter assembly usable with the actuator mechanisms of FIGS. 5and 6. The control catheter 40 may be dimensioned to be inserted withthe support structure through a biological lumen, such as a humanartery. As shown, the control catheter 40 includes a flexible drivecable 42 having a driver 44 on its distal end that removably mates witha hex head 37, 37′ of the actuator mechanism (FIGS. 5 and 6). Theproximal end of the cable 42 can include a hex head 46. In operation,the proximal hex head 46 of the cable 42 may be rotated by a surgeon,using a thumb wheel or other suitable manipulator (not shown). Rotationof the hex head 46 may be transferred by the cable 42 to the driver head44 to turn the actuator rod 30, 30′ (FIGS. 5 and 6).

The cable 42 may be encased by a flexible outer sheath 48. The distalend of the outer sheath 48 may include a lip or protuberance 49 shapedto interface with the support structure 10. When the cable 42 is turned,the outer sheath lip 49 may interact with the support structure 10 tocounteract the resulting torque.

By employing threads, the rod may be self-locking to maintain thesupport structure in the desired diameter. In a particular embodiment,the rod 32, 32′ may have a diameter of about 1.0 mm and a thread countof about 240 turns/inch. While a threaded rod and drive mechanism aredescribed, other techniques can be employed to actuate the linkagesdepending on the particular surgical application. For example, theactuator mechanism can be disposed within the thickness of the strutmembers, instead of inside or outside of the stent. For example, wormgears or a rack and pinion mechanism can be employed as known in theart. One of ordinary skill in the art should recognize other endoluminalactuation techniques. In other situations, the support structure can beimplanted during an open procedure, which may not require an externalactuation mechanism.

Although there are other uses for the described support structure, suchas drug delivery, a particular embodiment supports a prosthetic valve.In particular, the support structure may be used in combination with aprosthetic valve, such as for an aortic valve replacement.

FIG. 8 is a perspective view of a particular rotating prosthetic valveassembly. The prosthetic valve 100 may comprise a three leafletconfiguration shown in an open position. The leaflets may be derivedfrom a biocompatible material, such as animal pericardium (e.g. bovine,porcine, equine), human pericardium, chemically treated pericardium,gluteraldehyde-treated pericardium, tissue engineered materials, ascaffold for tissue engineered materials, autologous pericardium,cadaveric pericardium, Nitinol, polymers, plastics, PTFE, or any othermaterial known in the art.

The leaflets 101 a, 101 b, 101 c may be attached to a stationarycylindrical member 105 and a non-stationary cylindrical member 107. Oneside of each leaflet 101 may be attached to the non-stationarycylindrical member 107. The opposing side of each leaflet 101 may beattached to the stationary cylindrical member 105. The attachment ofeach leaflet 101 may be in a direction generally perpendicular to thelongitudinal axis of the cylindrical members 105, 107. In thisembodiment, each leaflet 101 may be pliable, generally rectangular inshape, and may have a 180 degree twist between its attachments tostationary member 105 and non-stationary member 107. Each leaflet 101may have an inner edge 102 and an outer edge 103, with the edges 102 c,103 c of one leaflet 101 c being referenced in the figure. As known inthe art, the leaflets can be fabricated from either biological ornon-biological materials, or a combination of both.

One way to actuate the valve to close may be by utilizing the forcesexerted by the normal blood flow or pressure changes of the cardiaccycle. More specifically, the heart may eject blood through the fullyopen valve in the direction of the arrow shown in FIG. 8. Shortlythereafter, the distal or downstream blood pressure may start to riserelative to the proximal pressure across the valve, which may create abackpressure on the valve.

FIG. 9 is a perspective view of the valve assembly of FIG. 8 while beingclosed. That backpressure along the direction of the arrow may case theaxially displacement of the leaflets 101 and non-stationary member 107towards the stationary cylindrical member 105. As the leaflets 101 movefrom a vertical to horizontal plane relative to the longitudinal axis, anet counter-clockwise torque force may be exerted on the non-stationarymember 107 and leaflets 101. The torque force may exert a centripetalforce on the leaflets 101.

FIG. 10 is a perspective view of the valve assembly of FIG. 8 oncecompletely closed. Complete closure of the valve 100 may occur as theleaflets 101 displace to the center of the valve and the non-stationarycylindrical member 107 rests upon the stationary member 105, as shown.

The function of the valve 100 opening can be understood by observing thereverse of the steps of valve closing, namely following the sequence ofdrawings from FIG. 10 to FIG. 8.

In considering the valve 100 as an aortic valve replacement, it mayremain closed as shown in FIG. 10, until the heart enters systole.During systole, as the myocardium forcefully contracts, the bloodpressure exerted on the valve's proximal side (the side closest to theheart) may be greater than the pressure on the distal side (downstream)of the closed valve. This pressure gradient causes the leaflets 101 andnon-stationary cylindrical member 107 to displace away from thestationary member 105 along the axial plane. The valve 100 may brieflyassume the half-closed transition state shown in FIG. 9.

As the leaflets 101 elongate from a horizontal to vertical orientationalong the axial plane, a net torque force may be exerted on the leaflets101 and non-stationary cylindrical member 107. Since the valve 100 isopening, as opposed to closing, the torque force exerted to open thevalve may be opposite to that exerted to close the valve. Given theconfiguration of embodiment shown in FIG. 9, the torque force that opensthe valve would be in clockwise direction.

The torque forces may cause the leaflets 101 to rotate with thenon-stationary member 107 around the longitudinal axis of the valve 100.This, in turn, may exert a centrifugal force on each leaflet 101. Theleaflets 101 may undergo radial displacement away from the center,effectively opening the valve and allowing blood to flow away from theheart, in the direction shown by the arrow in FIG. 8.

To summarize, the valve may passively function to provide unidirectionalblood flow by linking three forces. Axial, torque, and radial forces maybe translated in a sequential and reversible manner, while encoding thedirectionality of prior motions. First, the axial force of blood flowand pressure may cause the displacement of the leaflets 101 andnon-stationary members 107 relative to the stationary member 105 alongthe axial plane. This may be translated into a rotational force on theleaflets 101 and non-stationary member 107. The torque force, in turn,may displace the leaflets 101 towards or away from the center of thevalve, along the radial plane, which may close or open the valve 100.The valve 100 passively follows the pathway of opening or closing,depending on the direction of the axial force initially applied to thevalve by the cardiac cycle.

In the body, the stationary cylindrical member 105 may be secured andfixed in position at the implant site, while the non-stationary member107 and distal ends of leaflets 101 may be free to displace along theaxial plane. In using the prosthetic valve as an aortic valvereplacement, the stationary member 105 could be secured in the aorticroot. As the blood pressure or flow from the heart, increases, the valve100 may change from its closed configuration to the open configuration,with blood ejecting through the valve 100.

Specific advantages of the rotating valve of FIGS. 8-10, along withfurther embodiments, are described in the above-incorporated parentprovisional patent application.

FIG. 11 is a perspective view of the valve of FIGS. 8-10 in combinationwith the support structure of FIG. 1. As shown in the closed position,the valve's stationary member 105 is attached to the support structure10. The valve's nonstationary member 107 may not be attached to thesupport structure 10. This may enable the non-stationary member 107 todisplace along the axial plane along with the leaflets 101 during valveopening or closing. In this particular embodiment, the valve 100 mayoccupy a position that is closer to one end of the support structure 10,as shown.

FIG. 12 is a perspective view of the valve of FIG. 11 in the openposition. As noted above, the non-stationary member 107 may not beattached to support structure 10, and may thus be free to displace alongthe axial plane, along with the leaflets 101. In this particularembodiment, during full opening, non-stationary member 107 and theleaflets 101 may remain within the confines of the support structure 10.

The stented valve 110 can be implanted during a closed procedure asdescribed above. However, because of the operation of the non-stationarymember within the body of the stent, the actuator mechanism to compressand expand the stent may not be disposed within the stent in such acase.

Further embodiments of the stented valve 110, positioning of the valvein the body, and procedures for implantation are described in theabove-incorporated parent provisional patent application. In addition, atissue valve can be draped on the support structure. Additionalembodiments should be apparent to those of ordinary skill in the art.

FIG. 13 is a perspective view of a traditional tissue valve mounted tothe support structure of FIG. 1. As shown, a stented valve 120 mayinclude a prosthetic tissue valve 121 attached to a support structure10, such as that described above.

The tissue valve 121 may include three pliable semi-circular leaflets121 a, 121 b, 121 c, which can be derived from biocompatible materialsas noted with reference to FIG. 8. Adjacent leaflets may be attached inpairs to commissures 123 x, 123 y, 123 z on the support structure 10. Inparticular, the commissures 123 x, 123 y, 123 z correspond tospaced-apart distal anchor points 13 x, 13 y, 13 z on the supportstructure 10. In an 18-strut stent, the commissures may be attached thestructure 10 via corresponding fasteners 25 at every third distal anchorpoint.

From the commissures, the leaflet sides may be connected to the adjacentdiagonal struts. That is, the sides of the first leaflet 121 a may besutured to the struts 11-Xa and 11-Za, respectively; the sides of thesecond leaflet 121 b may be sutured to the struts 11-Xb and 11-Yb,respectively; and the sides of the third leaflet 121 c may be sutured tothe struts 11-Yc and 11-Zc, respectively. Those sutures may end at thescissor pivot points on the diagonal struts.

In the configuration shown, neighboring struts 11 may be attached to oneanother in a manner that creates multiple arches 128 at the ends of thestent. Posts for leaflet attachment, or commissures, may be formed byattaching a corresponding leaflet to each of the struts that define asuitable arch 128 x, 128 y, 128 z. In the configuration shown, there maybe three leaflets 121 a, 121 b, 121 c, each of which is attached to astrut along two of its opposing borders. The commissures may be formedby three equi-distant arches 128 x, 128 y, 128 z in the stent.

The angled orientation of a strut in relationship to its neighboringstrut may permit the leaflets 121 a, 121 b, 121 c to be attached to thestent in a triangular configuration. This triangular configurationsimulates the angled attachment of the native aortic leaflet. In thenative valve this creates an anatomical structure between leaflets,known as the inter-leaflet trigone. Because the anatomical inter-leaflettrigone is believed to offer structural integrity and durability to thenative aortic leaflets in humans, it may be advantageous to simulatethis structure in a prosthetic valve.

One method of attachment of the leaflets to the struts is to sandwichthe leaflet between a multi-ply strut. The multiple layers may then beheld together by sutures, or the attachment may be sutureless.Sandwiching the leaflets between the struts may help to dissipate theforces on leaflets and prevent the tearing of sutures through theleaflets.

The remaining side of each leaflet 121 a, 121 b, 121 c may be suturedannularly across the intermediate strut members as shown by a leafletseam. The remaining open spaces between the struts can be draped by abiocompatible skirt 125 to help seal the valve against the implant siteand thus limit paravalvular leakage. As shown, the skirt 125 may beshaped to cover those portions of the stent below and between the valveleaflets.

In more detail, the skirt 125 at the base of the valve may be a thinlayer of material that lines the stent wall. The skirt material can bepericardial tissue, polyester, PTFE, or other material or combinationsof materials suitable for accepting tissue in growth, includingchemically treated materials to promote tissue growth or inhibitinfection. The skirt layer may function to reduce or eliminate leakagearound the valve, or “paravalvular leak.” To that end, there are anumber of ways to attach the skirt material layer to the stent,including:

-   -   the skirt layer can be on the inside or the outside of the        stent;    -   the skirt layer can occupy the lower portion of the stent;    -   the skirt layer can occupy the lower and upper portion of the        stent;    -   the skirt layer can occupy only the upper portion of the stent;    -   the skirt layer can occupy the area between the struts that        define the commissure posts;    -   the skirt layer can be continuous with the leaflet material;    -   the skirt layer can be sutured to the struts or a multitude of        sites; or    -   the skirt layer can be secured to the lower portion of the        stent, and pulled or pushed up to cover the outside of the stent        during the deployment in the body.

The above list is not necessarily limiting as those of ordinary skill inthe art may recognize alternative draping techniques for specificapplications.

FIG. 14 is a perspective view of the valve structure of FIG. 13 having afull inner skirt. A stented valve 120′ may include a prosthetic tissuevalve 121′ having three leaflets 121 a′, 121 b′, 121 c′ attached to asupport structure 10. A skirt layer 125′ may cover the interior surfaceof the stent 10. As such, the valve leaflets 121 a′, 121 b′, 121 c′ maybe sutured to the skirt layer 125′.

FIG. 15 is a perspective view of the valve structure of FIG. 13 having afull outer skirt. A stented valve 120″ may include a prosthetic tissuevalve 121″ having three leaflets 121 a″, 121 b″, 121 c″ attached to asupport structure 10, such as that described in FIG. 13. A skirt layer125″ may cover the exterior surface of the stent 10.

The tissue valve structures 120, 120′, 120″ can also be implanted duringa closed procedure as described above. However, the actuator mechanismto compress and expand the stent may be attached to avoid the commissurepoints and limit damage to the skirt layer 125, 125′, 125″, such as bymounting the actuator mechanism on the outer surface of the stent 10.

While the above-described embodiments have featured a support structurehaving linear strut bars and equal length scissor arms, other geometriesmay be employed. The resulting shape may be other than cylindrical andmay have different performance characteristics in certain applications.

For example, FIG. 25 is a perspective view of another support structureto which a traditional tissue valve may be mounted. The supportstructure may have a generally tubular shape comprising a proximalopening 2520, distal opening 2530, and a lumen 2540 therebetween. Thetubular shape may be shorter and ring like as in the support structure2510 in FIG. 25, or in other variations it may be elongate.

Like the support structure in FIG. 1, this support structure 2510 mayinclude a plurality of longitudinal strut members 2511 and commissurestrut members 2519 interconnected by a plurality articulationscomprising pin or rotatable joints 2515. The commissure strut members2519 and their articulations may permit regions of the support structureto extend further beyond the structure provided by the longitudinalstrut members 2511, and which may expand and contract along with theconfigurational changes to the longitudinal strut members 2511, withoutgenerating significantly more resistance or stress in the structure, ifany. As shown, there are eighteen struts 2511 and six struts 2519. Thepin or rotatable joints 2515 may have an axis of rotation with a radialorientation and which may allow the interconnected strut members 2511and 2519 to rotate relative to each other. One set of pin joints 2515connecting longitudinal strut members 2511 may be located at theproximal ends of strut members 2511 in a plane aligned with the proximalopening 2520. A second set of pin joints 2511 connecting longitudinalstrut members 2511 may be located at the distal ends of strut members2511 in a plane aligned with the distal opening 2530. A third set of pinjoints 2511 connecting longitudinal strut members 2511 may be locatedbetween the proximal opening 2520 and the distal opening 2530. A fourthset of pin joints 2511 connecting commissure strut members 2519 may belocated distal to the plane of distal opening 2530. A fifth set of pinjoints 2511 connecting longitudinal strut members 2511 to commissurestrut members 2519 may be located proximal to the plane of distalopening 2530 between the third set of pin joints 2511 and the plane ofdistal opening 2530.

As in support structure 10 (FIG. 1), longitudinal strut members 2511 maybe fabricated from a rigid or semi-rigid biocompatible material, such asplastics or other polymers and metal alloys, including stainless steel,tantalum, titanium, nickel-titanium (e.g. Nitinol), and cobalt-chromium(e.g. ELGILOY). The dimensions of each strut can be chosen in accordancewith its desired use. As shown, each longitudinal strut member 2511 isbar shaped and has a front surface 2511 f and a back surface 2511 b. Ina particular embodiment, each strut member may be made from stainlesssteel, which may be about 0.001-0.100 inch thick. More particularly,each strut may be about 0.01 inch thick 300 series stainless steel. Inanother embodiment, each strut member may be made from cobalt-chromium(e.g. ELGILOY). While all struts 2511 are shown as being of uniformthickness, the thickness of a strut can vary across a strut, such as agradual increase or decrease in thickness along the length of a strut.Furthermore, individual struts 2511 can differ in thickness from otherindividual struts 2511 in the same support structure. In a particularembodiment, each strut member 2511 may be about 0.01-0.25 inches wide.More particularly, each strut 2511 may be about 0.06 inches wide. Whileall struts 2511 are shown as being of a uniform width, a strut can varyin width along its length. Furthermore, an individual strut 2511 canhave a different width than another strut 2511 in the same supportstructure 2510. The particular dimensions can be chosen based on theimplant site. The strut lengths can vary from strut to strut within thesame support structure, as is explained in detail below.

Commissure strut members 2519 may be fabricated from the same materialsas described above for longitudinal strut members 2511 above, or in somevariations they are fabricated from biocompatible materials havinggreater flexibility than the materials from which longitudinal strutmembers 2511 are fabricated. Such biocompatible materials can includeplastics or other polymers and metal alloys, including stainless steel,Nitinol, cobalt-chromium, and the like. The dimensions of eachcommissure strut 2519 can be chosen in accordance with its desired use.As shown, each longitudinal strut member 2519 is bar shaped and has afront surface 2519 f and a back surface 2519 b. In a particularembodiment, each strut member can be made from stainless steel, whichmay be about 0.001-0.100 inch thick. More particularly, each strut maybe about 0.01 inch thick 300 series stainless steel. In anotherembodiment, each strut member may be made from cobalt-chromium (e.g.ELGILOY). While all struts 2519 are shown as being of uniform thickness,the thickness of a strut can vary across a strut, such as a gradualincrease or decrease in thickness along the length of a strut.Furthermore, individual struts 2519 can differ in thickness from otherindividual struts 2519 in the same support structure. In a particularembodiment, each strut member 2519 may be about 0.01-0.25 inches wide.More particularly, each strut 2519 may be about 0.06 inches wide. Whileall struts 2519 are shown as being of a uniform width, a strut can varyin width along its length. Furthermore, an individual strut 2519 canhave a different width than another strut 2519 in the same supportstructure 2510. The particular dimensions can be chosen based on theimplant site. The strut lengths can vary from strut to strut within thesame support structure, as is explained in detail below.

The strut members can, however, optionally comprise differentgeometries. For instance, the longitudinal struts 2511 and commissurestruts 2519 can be non-flat structures. In particular, the struts caninclude a curvature, such as in a concave or convex manner inrelationship to the inner diameter of the support structure 2510. Thestruts can also be twisted. The nonflatness or flatness of the strutscan be a property of the material from which they are constructed. Forexample the struts can exhibit shape-memory or heat responsive changesin shape to the struts during various states. Such states can be definedby the support structure in the compressed or expanded configuration.The struts can also exhibit changes in shape due to stressed on themwhile implanted. For instance, if used to support a prosthetic valveassembly as described in detail below, the stress on the commissurestruts 2519 during the normal cardiac cycle may cause the commissurestruts 2519 to permanently or temporarily bend or otherwise changeshape. In variations in which the commissure strut members 2519 arefabricated from biocompatible materials having greater flexibility thanthe materials from which the longitudinal strut members 2511 arefabricated, if a force including a radially inward component is appliedto the commissure strut members, they may flex inward, while thelongitudinal strut members 2511 may not substantially deform.

Furthermore, the strut members 2511 and 2519 can have a smooth or roughsurface texture. In particular, a pitted surface can provide tensilestrength to the struts. In addition, roughness or pitting can provideadditional friction to help secure the support structure at the implantsite and encourage encapsulation of the support structure 2510 by tissuegrowth to further stabilize and support structure 2510 at the implantsite over time.

In certain instances, the support structure 2510 could be comprised ofstruts that are multiple members stacked upon one another. Within thesame stent, some struts could include elongated members stacked upon oneanother in a multi-ply configuration, and other struts could be one-ply,composed of single-thickness members. Within a single strut, there canbe areas of one-ply and multi-ply layering of the members.

Each longitudinal strut member 2511 may also include a plurality oforifices 2513 spaced along the length of strut members 2511. On thefront surface 2511 f, orifices may be countersunk to receive the head ofa fastener. The orifices 2513 are shown as being of uniform diameter anduniform spacing along the strut members 2511, but neither is required.FIG. 25 shows commissure strut members 2519 as not having orifices 2513along their lengths. However, in other instances, the commissure strutmembers 2519 can have orifices 2513 along their lengths. Orifices 2513on commissure strut members 2519 can similarly be countersunk on frontsurface 2519 f to receive the head of a fastener. Orifices 2513 oncommissure strut members 2519 can also similarly be of uniform diameterand uniform spacing along strut members 2519, but again neither isrequired. The orifices 2513 can receive fasteners as described in detailbelow, and then can provide an additional pathway for tissue growth-overto stabilize and encapsulate support structure 2510 over time. In FIG.25, longitudinal strut members 2511-1 and 2511-4 (FIG. 26) have thirteenorifices 2513 and longitudinal strut members 2511-2 and 2511-3 (FIG. 26)have ten orifices 2513. There can, however, be more or fewer orifices onlongitudinal strut members 2511.

The strut members 2511 and 2519 may be arranged as a chain of four- andsix-bar linkages, and wherein at least some, if not all, of the linkagesets share common struts with adjacent linkages and configurationchanges to one linkage will generate complementary changes to the otherlinkages linked by common struts. Complementary changes, however, arenot necessarily limited to linkages or struts with common struts. Thefour-bar linkages may have the same configuration as the four strutsection of the stent of FIG. 1, shown in FIG. 2 and described in detailabove. FIG. 26 is a perspective view of a six-bar linkage of the supportstructure of FIG. 25. As shown, two outer strut members 2511-1, 2511-3overlap two inner strut members 2511-2, 2511-4, with their back surfacesin communication with each other. In addition, two commissure strutmembers—outer commissure strut member 2519-1 and inner commissure strutmember 2519-2—can be connected to inner strut member 2511-2 and outerstrut member 2511-3. The strut members 2511, 2519 may be interconnectedby rotatable or swivelable pivot fasteners 2525, such as rivets,extending through aligned orifices. It should be understood that otherrotatable or swivelable fasteners 2525 can be employed such as screws,bolts, ball-in-socket structures, nails, or eyelets, and that thefasteners can be integrally formed in the struts 2511, 2519 such as apeened semi-sphere interacting with an indentation or orifice, or amale-female coupling.

In particular, the outer strut member 2511-1 may be rotatably orswivelably connected to the inner strut member 2511-2 by a pin joint2515-1 using a rivet 2525-1, which utilizes orifices 2913. The pin joint2525-1 may bisect outer strut member 2511-1. The pin joint 2525-1 maynot bisect inner strut member 2511-2, but instead utilize an orifice2513 that is offset distally from the longitudinal center of inner strutmember 2511-2. It should be understood that the joint 2515-1 may utilizedifferent orifices 2513 than the ones shown in FIG. 26.

The outer strut member 2511-3 may be rotatably connected to the innerstrut member 2511-4 by a pin joint 2515-7 using a rivet 2525-7, whichutilizes orifices 13. The pin joint 2525-7 may bisect inner strut member2511-4. The pin joint 2525-7 may not bisect outer strut member 2511-3,but instead utilize an orifice 2513 that is offset distally from thelongitudinal center on outer strut member 2511-3. It should beunderstood that the joint 2515-7 may utilize different orifices 2513than the ones shown in FIG. 26.

In addition to the joint 2515-1, the outer strut member 2511-1 may berotatably connected to the inner strut member 2511-4 by a proximalanchor pin joint 2515-3 using rivet 2525-3, located near the proximalends of the strut members 2511-1, 2511-4. The inner strut member 2511-2may also be rotatably connected to the commissure strut member 2519-1 bya pin joint 2515-9 using a rivet 2525-9, located near the distal end ofinner strut member 2511-2 and the proximal end of commissure strutmember 2519-1. Likewise, the outer strut member 2511-3 may be rotatablyconnected to the commissure strut member 2519-2 by a pin joint 2515-11using a rivet 2525-11, located near the distal end of outer strut member2511-3 and the proximal end of commissure strut member 2519-2.Commissure strut member 2519-1 may also be rotatably connected tocommissure strut member 2519-2 by a distal anchor pin joint 2515-13using rivet 2525-13, located near the distal ends of the commissurestrut members 2519-1, 2519-2.

Strut members 2511, 2519 may have lengths chosen based on the implantsite. In a particular embodiment, outer longitudinal strut 2511-1 andinner longitudinal strut 2511-4 may have approximately the same length,inner longitudinal strut 2511-2 and outer longitudinal strut 2511-3 mayhave approximately the same length, and commissure struts 2519-1, 2519-2may have approximately the same length. In that embodiment the length ofouter longitudinal strut 2511-1 and inner longitudinal strut 2511-4 maybe greater than the length of inner longitudinal strut 2511-2 and outerlongitudinal strut 2511-3. In that embodiment, the combined longitudinallength of longitudinal strut member 2511-2 and commissure strut member2519-1 may be greater than the length of longitudinal strut member2511-1 or longitudinal strut member 2511-4. In that embodiment, thecombined longitudinal length of longitudinal strut member 2511-3 andcommissure strut member 2519-2 may be greater than the length oflongitudinal strut member 2511-1 or longitudinal strut member 2511-4. Insome embodiments the combined length of longitudinal strut member 2511-2and commissure strut member 2519-1 may be at least 20% longer than thelength of longitudinal strut members 2511-1 or 2511-4. Similarly thecombined longitudinal length of longitudinal strut member 2511-3 andcommissure strut member 2519-2 may be at least 20% longer than thelength of longitudinal strut members 2511-1 or 2511-4. Distal anchor pinjoint 2515-13, located near the distal ends of commissure strut members2519-1 and 2519-2 may extend beyond the plane of the distal opening 2530by a longitudinal distance that is at least 20% of the longitudinaldistance between the planes of the proximal opening 2520 and distalopening 2530. In one embodiment outer longitudinal strut 2511-1 andinner longitudinal strut 2511-4 may be about 0.250-3.00 inches long;inner longitudinal strut 2511-2 and outer longitudinal strut 2511-3 maybe about 0.1-2.5 inches long; and commissure struts 2519-1, 2519-2 maybe about 0.1-2.5 inches long. More particularly, outer longitudinalstrut 2511-1 and inner longitudinal strut 2511-4 may be about 0.5 incheslong; inner longitudinal strut 2511-2 and outer longitudinal strut2511-3 may be about 0.375 inches long; and commissure struts 2519-1,2519-2 may be about 0.2 inches long.

To reduce stress on the anchor rivets 2525-3, 2525-13, the proximal endsof struts 2511-1, 2511-4 and distal ends of commissure struts 2519-1,2519-2 may be curved or twisted to provide a flush interface between thejoined struts.

As can be seen in FIG. 25, the support structure 2510 may be fabricatedby linking together a chain of individual six-strut sections (FIG. 26)and four-strut sections (FIG. 2). The chain may then be wrapped orotherwise connected back to itself to join the last section with thefirst section in the chain. As shown in FIG. 25, a chain of threesix-strut sections and six four-strut sections may be joined, such thatevery third section is a six-strut section. It should be understood thatdifferent numbers of four-strut sections may be linked with the threesix-strut sections. In some variations, the support structure may havezero four-strut sections and consist only of six-strut sections. As inthe support structure 10 shown in FIG. 1, actuating the linkage maycause the links to be opened or closed, which may result in expanding orcompressing the support structure 2510 (FIG. 25). When the supportstructure is in neither a fully expanded nor fully compressed state, theangle between commissure strut members 2519-1, 2519-2 at distal anchorpin joint 2515-13 may be less than the angle between two longitudinalstrut members 2511 at an anchor pin joint 2515 located near the distalends of the two longitudinal strut members 2511. The diameter of supportstructure 2510 can be chosen based on the implant site. In a particularembodiment for implantation at the mitral valve opening, the diametermay be about 0.5-1.55 inches. More particularly, the diameter may beabout 0.8 inches.

FIG. 28 is a perspective view of a traditional tissue valve mounted tothe support structure of FIG. 25. As shown, a stented valve 2800 mayinclude a prosthetic tissue valve 121, as described above, to a supportstructure 2510, as described above. Adjacent leaflets may be attached inpairs to commissures 123 x, 123 y, 123 z on support structure 2510,which correspond to the distal pin joints 2515 located at the distalends of commissure strut members 2519.

From the commissures, the leaflet sides may be connected to the adjacentstruts. That is, the sides of the first leaflet 121 a may be sutured tothe struts 2511 a-1, 2519 a-1, 2511 a-2, 2519 a-2; the sides of thesecond leaflet 121 b may be sutured to the struts 2511 b-1, 2519 b-1,2511 b-2, 2519 b-2; and the sides of the third leaflet 121 c may besutured to the struts 2511 c-1, 2519 c-1, 2511 c-2, 2519 c-2. Thosesutures end at the scissor pivot points 2515 on the longitudinal struts2511.

Like the attachment of leaflets to support structure 10 shown in FIG.13, the angled orientation of a strut in relationship to its neighboringstrut may enable the leaflets 121 a, 121 b, 121 c to be attached to thestent in a triangular configuration. This triangular configuration maysimulate the angled attachment of the native leaflet and allow foranatomical draping of the tissue. In the native valve this creates ananatomical structure between leaflets, known as the inter-leaflettrigone. Because the anatomical inter-leaflet trigone is believed tooffer structural integrity and durability to the native leaflets inhumans, it is advantageous to simulate this structure in a prostheticvalve.

The tissue valve mounted to support structure shown in FIG. 25 may alsobe modified to sandwich the leaflets between multi-ply struts, and todrape the open spaces between the struts with a biocompatible skirt, asdescribed in more detail above regarding FIGS. 14-15.

In another embodiment, the tissue valve 121 may be mounted to thesupport structure 2510 in a secure, sutureless manner. Leaflets 121 a,121 b, 121 c can be suturelessly attached at the distal tip ofcommissures 123 x, 123 y, 123 z, and along the distal portion of struts2511. In some variations, the leaflets 121 a, 121 b, 121 c can also besuturelessly attached along struts 2519. More particularly, the sides ofleaflet 121 a may be suturelessly attached to the struts 2511 a-1, 2511a-2; the sides of leaflet 121 b may be suturelessly attached to thestruts 2511 b-1, 2511 b-2; and the sides of leaflet 121 c may besuturelessly attached to the struts 2511 c-1, 2511 c-2. In somevariations, the sides of leaflet 121 a can be suturelessly attached tothe struts 2919 a-1, 2519 a-2; the sides of leaflet 121 b can besuturelessly attached to the struts 2519 b-1, 2519 b-2; and the sides ofleaflet 121 c can be suturelessly attached to the struts 2519 c-1, 2519c-2.

The sutureless attachments may be formed by draping the leaflets overthe distal tips of commissures 123 x, 123 y, 123 z; sandwiching theleaflets between struts at pivot joints; or sandwiching the leafletsbetween multi-ply struts. More particularly, the sides of leaflet 121 acan be sandwiched between the commissure strut 2519 c-1 and commissurestrut 2519 a-2 at the pivot joint at distal tip of commissure 123 z;sandwiched between commissure strut 2519 a-2 and longitudinal strut 2511a-2 at the connecting pivot joint; sandwiched between longitudinal strut2511 a-2 and the rotatably attached longitudinal strut 2511 at themiddle pivot joint 2515; sandwiched between commissure strut 2519 a-1and commissure strut 2519 b-2 at the pivot joint at distal tip ofcommissure 123 x; sandwiched between commissure strut 2519 a-1 andlongitudinal strut 2511 a-1 at the connecting pivot joint; andsandwiched between longitudinal strut 2511 a-1 and the rotatablyattached longitudinal strut 2511 at the middle pivot joint 2515. Therivets 2525 at these pivot joints may pass through the leaflet 121 a.

The sides of leaflet 121 b can be sandwiched between the commissurestrut 2519 a-1 and commissure strut 2519 b-2 at the pivot joint atdistal tip of commissure 123 x; sandwiched between commissure strut 2519b-2 and longitudinal strut 2511 b-2 at the connecting pivot joint;sandwiched between longitudinal strut 2511 b-2 and the rotatablyattached longitudinal strut 2511 at the middle pivot joint 2515;sandwiched between commissure strut 2519 b-1 and commissure strut 2519c-2 at the pivot joint at distal tip of commissure 123 y; sandwichedbetween commissure strut 2519 b-1 and longitudinal strut 2511 b-1 at theconnecting pivot joint; and sandwiched between longitudinal strut 2511b-1 and the rotatably attached longitudinal strut 2511 at the middlepivot joint 2515. The rivets 2525 at these pivot joints may pass throughthe leaflet 121 b.

The sides of leaflet 121 c can be sandwiched between the commissurestrut 2519 b-1 and commissure strut 2519 c-2 at the pivot joint atdistal tip of commissure 123 y; sandwiched between commissure strut 2519c-2 and longitudinal strut 2511 c-2 at the connecting pivot joint;sandwiched between longitudinal strut 2511 c-2 and the rotatablyattached longitudinal strut 2511 at the middle pivot joint 2515;sandwiched between commissure strut 2519 c-1 and commissure strut 2519a-2 at the pivot joint at distal tip of commissure 123 z; sandwichedbetween commissure strut 2519 c-1 and longitudinal strut 2511 c-1 at theconnecting pivot joint; and sandwiched between longitudinal strut 2511c-1 and the rotatably attached longitudinal strut 2511 at the middlepivot joint 2515. The rivets 2525 at these pivot joints may pass throughthe leaflet 121 c.

In another embodiment, struts 2511 a-1, 2511 a-2, 2511 a-3, 2511 b-1,2511 b-2, 2511 b-3, 2511 c-1, 2511 c-2, 2511 c-3, 2519 a-1, 2519 a-2,2519 a-3, 2519 b-1, 2519 b-2, 2519 b-3, 2519 c-1, 2519 c-2, 2519 c-3 aremulti-ply struts, and the leaflets 121 a, 121 b, 121 c are sandwichedbetween the two or more layers of the struts. More particularly, oneside of leaflet 121 a may be sandwiched within the multi-ply strutmaking up commissure strut 2519 a-1 and the multi-ply strut making upthe distal portion of longitudinal strut 2511 a-1, and the other side ofleaflet 121 a may be sandwiched within the multi-ply strut making upcommissure strut 2519 a-1 and the multi-ply strut making up the distalportion of longitudinal strut 2511 a-2. One side of leaflet 121 b may besandwiched within the multi-ply strut making up commissure strut 2519b-1 and the multi-ply strut making up the distal portion of longitudinalstrut 2511 b-1, and the other side of leaflet 121 b may be sandwichedwithin the multi-ply strut making up commissure strut 2519 b-1 and themulti-ply strut making up the distal portion of longitudinal strut 2511b-2. One side of leaflet 121 c may be sandwiched within the multi-plystrut making up commissure strut 2519 c-1 and the multi-ply strut makingup the distal portion of longitudinal strut 2511 c-1, and the other sideof leaflet 121 c may be sandwiched within the multi-ply strut making upcommissure strut 2519 c-1 and the multi-ply strut making up the distalportion of longitudinal strut 2511 c-2.

In order to facilitate secure, suture-free leaflet attachment duringfabrication through sandwiching of the leaflets between the struts, theleaflets 121 a, 121 b, 121 c may comprise a shape as shown in FIG. 34having a central region 3401 having a semicircular or paraboloid shape,with two rectangular regions extending from each side of the centralregion 3401. The upper rectangular regions 3403 may be sandwiched withinmulti-ply struts making up commissure struts 2519, and the lowerrectangular regions 3405 may be sandwiched within multi-ply strutsmaking up longitudinal struts 2511. After the upper regions 3403 andlower regions 3405 are sandwiched between the struts, the outer portionsof the regions 3403, 3405 can be removed (e.g. by being cut off),leaving the central region 3401 suturelessly attached to the supportstructure 2510.

In other embodiments, tissue valves may be mounted to the other supportstructures described herein, such as the support structure shown inFIGS. 13-15 and the support structure 2710 shown in FIG. 27A, in thesutureless manner described above.

FIG. 27A is a perspective view of another support structure to which atraditional tissue valve can be mounted. The support structure may havea tubular shape having a proximal opening 2720, distal opening 2730, anda lumen 2740 therebetween. The tubular shape may be shorter and ringlike as in the support structure 2710 in FIG. 27A, or in othervariations it may be elongate.

Like the support structures in FIGS. 1 and 25, support structure 2710may include a plurality of longitudinal strut members 2711 andcommissure strut members 2719 interconnected by a plurality of pinjoints 2715. As shown, there are twelve struts 2711 and six struts 2719.The pin joints 2715 may have an axis of rotation with radialorientation, which may allow the interconnected strut members 2711 and2719 to rotate relative to each other. One set of pin joints 2715connecting longitudinal strut members 2711 may be located at theproximal ends of strut members 2711 in a plane aligned with proximalopening 2720. A second set of pin joints 2711 connecting longitudinalstrut members 2711 to each other and to commissure strut members 2719may be located at the distal ends of longitudinal strut members 2711 andthe proximal ends of commissure strut members 2719 and in a planealigned with the distal opening 2730. A third set of pin joints 2711connecting longitudinal strut members 2711 may be located between theproximal opening 2720 and distal opening 2730 and proximal to themidpoint between the proximal opening 2720 and distal opening 2730. Afourth set of pin joints 2711 may be located between the proximalopening 2720 and distal opening 2730 and distal to the midpoint betweenthe proximal opening 2720 and distal opening 2730. A fifth set of pinjoints 2711 connecting commissure strut members 2719 may be locateddistal to the plane of distal opening 2530.

As in support structures 10 (FIG. 1) and 2510 (FIG. 25), longitudinalstrut members 2711 may be fabricated from a rigid or semi-rigidbiocompatible material, such as plastics or other polymers and metalallows, including stainless steel, tantalum, titanium, nickel-titanium(e.g. Nitinol), and cobalt-chromium (e.g. ELGILOY). The dimensions ofeach strut can be chosen in accordance with its desired use. As shown,each longitudinal strut member 2711 is bar shaped and has a frontsurface 2711 f and a back surface 2711 b. In a particular embodiment,each strut member may be made from stainless steel, which may be about0.001-0.100 inch thick. More particularly, each strut may be about 0.01inch thick 300 series stainless steel. In another embodiment, each strutmember is made from cobalt-chromium (e.g. ELGILOY). While all struts2711 are shown as being of uniform thickness, the thickness of a strutcan vary across a strut, such as a gradual increase or decrease inthickness along the length of a strut. Furthermore, individual struts2711 can differ in thickness from other individual struts 2711 in thesame support structure. In a particular embodiment, each strut member2711 may be about 0.01-0.25 inches wide. More particularly, each strut2711 may be about 0.06 inches wide. While all struts 2711 are shown asbeing of a uniform width, a strut can vary in width along its length.Furthermore, an individual strut 2711 can have a different width thananother strut 2711 in the same support structure 2710. The particulardimensions can be chosen based on the implant site. The strut lengthscan vary from strut to strut within the same support structure, as isexplained in detail below.

Commissure strut members 2719 may be fabricated from the same materialsas described above for longitudinal strut members 2711 above, or in somevariations they are fabricated from biocompatible materials havinggreater flexibility than the materials from which longitudinal strutmembers 2711 are fabricated. Such biocompatible materials can includethe materials as described elsewhere herein. The dimensions of eachcommissure strut 2719 can be chosen in accordance with its desired use.As shown, each longitudinal strut member 2719 is bar shaped and has afront surface 2719 f and a back surface 2719 b. In a particularembodiment, each strut member may be made from stainless steel, whichmay be about 0.001-0.100 inch thick. More particularly, each strut maybe about 0.01 inch thick 300 series stainless steel. While all struts2719 are shown as being of uniform thickness, the thickness of a strutcan vary across a strut, such as a gradual increase or decrease inthickness along the length of a strut. Furthermore, individual struts2719 can differ in thickness from other individual struts 2719 in thesame support structure. In a particular embodiment, each strut member2719 may be about 0.010-0.250 inches wide. More particularly, each strut2719 may be about 0.06 inches wide. While all struts 2719 are shown asbeing of a uniform width, a strut can vary in width along its length.Furthermore, an individual strut 2719 can have a different width thananother strut 2719 in the same support structure 2710. The particulardimensions can be chosen based on the implant site. The strut lengthscan vary from strut to strut within the same support structure, as isexplained in detail below.

The strut members can however be of different geometries. For instance,the longitudinal struts 2711 and commissure struts 2719 can be non-flatstructures. In particular, the struts can include a curvature, such asin a concave or convex manner in relationship to the inner diameter ofthe support structure 2710. The struts can also be twisted. Thenonflatness or flatness of the struts can be a property of the materialfrom which they are constructed. For example the struts can exhibitshape-memory or heat responsive changes in shape to the struts duringvarious states. Such states can be defined by the support structure inthe compressed or expanded configuration. The struts can also exhibitchanges in shape due to stressed on them while implanted. For instance,if used to support a prosthetic valve assembly as described in detailbelow, the stress on the commissure struts 2719 during the normalcardiac cycle may cause the commissure struts 2719 to permanently ortemporarily bend or otherwise change shape. In variations in which thecommissure strut members 2719 are fabricated from biocompatiblematerials having greater flexibility than the materials from which thelongitudinal strut members 2711 are fabricated, if a force including aradially inward component is applied to the commissure strut members,they may flex inward, while the longitudinal strut members 2711 may notsubstantially deform.

Furthermore, the strut members 2711 and 2719 can have a smooth or roughsurface texture. In particular, a pitted surface can provide tensilestrength to the struts. In addition, roughness or pitting can provideadditional friction to help secure the support structure at the implantsite and encourage encapsulation of the support structure 2710 by tissuegrowth to further stabilize and support structure 2710 at the implantsite over time.

In certain instances, the support structure 2710 could be comprised ofstruts that are multiple members stacked upon one another. Within thesame stent, some struts could include elongated members stacked upon oneanother in a multi-ply configuration, and other struts could be one-ply,composed of single-thickness members. Within a single strut, there canbe areas of one-ply and multi-ply layering of the members.

Each longitudinal strut member 2711 may also include a plurality oforifices 2713 spaced along the length of strut members 2711. On thefront surface 2711 f, orifices may be countersunk to receive the head ofa fastener. The orifices 2713 are shown as being of uniform diameter anduniform spacing along the strut members 2711, but neither is required.FIG. 27A shows commissure strut members 2719 as not having orifices 2713along their lengths. However, in other instances the commissure strutmembers 2719 can have orifices 2713 along their lengths. Orifices 2713on commissure strut members 2719 can similarly be countersunk on frontsurface 2719 f to receive the head of a fastener. Orifices 2713 oncommissure strut members 2719 can also similarly be of uniform diameterand uniform spacing along strut members 2719, but again neither isrequired. The orifices 2713 can receive fasteners as described in detailbelow, and then can provide an additional pathway for tissue growth-overto stabilize and encapsulate support structure 2710 over time. In FIG.27A, longitudinal strut members 2711 have five orifices 2713. There can,however, be more or fewer orifices on longitudinal strut members 2711.For example, in another embodiment, longitudinal struts 2711-2, 2711-3may have four orifices 2713, and longitudinal struts 2711-1, 2711-4 mayhave no orifices. In another embodiment, longitudinal struts 2711-2,2711-3 may have no orifices, and longitudinal struts 2711-1, 2711-4 mayhave four orifices 2713.

The strut members 2711 and 2719 may be arranged as a chain of threesix-strut elements. Each six-strut element may contain two outer strutmembers 2711-1, 2711-3, which overlap two inner strut members 2711-2,2711-4, with their back surfaces in communication with each other. Inaddition, each inner and outer strut member may be connected to one oftwo commissure strut members—outer commissure strut member 2719-1 orinner commissure strut member 2719-2. The strut members 2711, 2719 maybe interconnected by rotatable pivot fasteners 2725, such as rivets,extending through aligned orifices. It should be understood that otherrotatable fasteners 2725 can be employed such as screws, bolts,ball-in-socket structures, nails, or eyelets, and that the fasteners canbe integrally formed in the struts 2711, 2719 such as a peenedsemi-sphere interacting with an indentation or orifice, or a male-femalecoupling.

In particular, the outer strut member 2711-1 may be rotatably connectedto the inner strut member 2711-2 by a distal pin joint 2715-2 usingrivet 2725-2, located near the distal ends of the strut members 2711-1,2711-2. The outer strut member 2711-3 may be rotatably connected to theinner strut member 2711-4 by a distal pin joint 2715-3 using rivet2725-3, located near the distal ends of the strut members 2711-3,2711-4. The outer strut member 2711-3 may also be rotatably connected tothe inner strut member 2711-2 by a pin joint 2715-1 using a rivet2725-1, which utilizes orifices 2713. The pin joint may be offsetdistally from the longitudinal center on both outer strut member 2711-3and inner strut member 2711-2. It should be understood that the joint2715-1 may utilize different orifices 2713 than the ones shown in FIG.27A, including being offset proximally from the longitudinal center.

The commissure strut member 2719-1 may be rotatably connected at itsproximal end to outer strut member 2711-1 and inner strut member 2711-2at pin joint 2715-2 using rivet 2725-2. The commissure strut member2719-2 may be rotatably connected at its proximal end to outer strutmember 2711-3 and inner strut member 2711-4 at pin joint 2715-3 usingrivet 2725-3.

Commissure strut member 2719-1 may be rotatably connected to commissurestrut member 2719-2 by a distal anchor pin joint 2715-4 using rivet2725-4, located near the distal ends of the commissure strut members2719-1, 2719-2.

Strut members 2711, 2719 may have lengths chosen based on the implantsite. In a particular embodiment, longitudinal strut members 2711 mayall have approximately the same length, and commissure strut members2719 may all have approximately the same length. In the variation shownin FIG. 27A, the commissure strut members 2719 have a shorter lengththan longitudinal strut members 2719. In other variations, thecommissure strut members 2719 may be longer than longitudinal strutmembers 2719. In one embodiment longitudinal strut members 2711 may beabout 0.25-3 inches long, and commissure strut members 2719 may be about0.25-2 inches long. More particularly, longitudinal strut members 2711may be about 1.75 inches long, and commissure strut members 2719 may beabout 1 inch long.

To reduce stress on the anchor rivets 2525-4, 2525-5, and 2525-6, theproximal ends of longitudinal strut members 2711 and distal ends ofcommissure strut members 2719 can be curved or twisted to provide aflush interface between the joined struts.

As can be seen, the support structure 2710 may be fabricated by linkingtogether a chain of three six-strut elements, and wherein at least some,if not all, of the linkage sets share common struts with adjacentlinkages and configuration changes to one linkage will generatecomplementary changes to the other linkages linked by common struts.Complementary changes, however, are not necessarily limited to linkagesor struts with common struts. Two such elements may be connected byrotatably connecting the outer strut member 2711-1 of a first element tothe inner strut member 2711-2 of a second element by a proximal anchorpin joint 2715-5 using rivet 2715-5, located near the proximal ends ofstrut member 2711-1 of the first element and strut member 2711-2 of asecond element. In addition, the outer strut member 2711-3 of the firstelement may be rotatably connected to the inner strut member 2711-4 ofthe second element by a proximal anchor pin joint 2715-6 using rivet2725-6, located near the proximal ends of strut member 2711-3 of thefirst element and strut member 2711-4 of the second element. Outer strutmember 2711-1 of the first element may also be rotatably connected toinner strut member 2711-4 of the second element by a pin joint 2715-7using rivet 2725-7, which utilizes orifices 2713. The pin joint may beoffset proximally from the longitudinal center on both the outer strutmember 2711-1 and inner strut member 2711-4. It should be understoodthat joint 2715-7 may utilize different orifices 2713 than the onesshown in FIG. 27A, including being offset distally from the longitudinalcenter. A third element may be connected to the second element in thesame manner as the second element is connected to the first element. Thechain may then be wrapped to join the third element with the firstelement in the same manner.

When the support structure 2710 is in neither a fully expanded nor fullycompressed state, the angles between the commissure strut members2719-1, 2719-2 at distal anchor pin joint 2715-4 may be less than theangle between two longitudinal strut members 2711 at other anchor pinjoints 2715-2, 2715-3, 2715-5, and 2715-6. In the embodiment in FIG. 27Athe angles between two longitudinal strut members 2711 at anchor pinjoints 2715-2, 2715-3, 2715-5, and 2715-6 are the same. In otherembodiments the angles may be different. The diameter of supportstructure 2710 can be chosen based on the implant site. In a particularembodiment for implantation at the mitral valve opening, the diametermay be about 0.5-1.5 inches. More particularly, the diameter may beabout 0.8 inches. In another embodiment for implantation at the aorticvalve opening, the diameter may be larger than the diameter of anembodiment for implantation at the mitral valve opening. Moreparticularly, the diameter may be about 0.5-2.0 inches. In a particularembodiment, the diameter may be about 1 inch. The diameter may be suchthat the valve is secured in the aortic valve opening by exerting astrong outward radial force against the tissue, forming a friction fit.

In an embodiment at the aortic valve opening, the overall height of thevalve support structure may be less, than the overall height of anembodiment for implantation at the mitral valve. In an embodiment theheight in the expanded configuration may be about 0.2-2.0 inches. Moreparticularly, the height in the expanded configuration may be about 0.6inches.

The support structure 2710 may be collapsible and may be able to bereversibly expanded or compressed by actuating the linkages to open orclose the links. When radially inward pressure is applied to one or morelongitudinal struts 2711, the support structure 2710 may compress. Whenradially outward pressure is applied to one or more longitudinal struts2711, the support structure 2710 may expand.

In another embodiment, a tissue valve 2721 may be mounted to the supportstructure 2710 in a secure, sutureless manner, as shown in FIG. 27B. Theorientation of attached leaflets may bias the tissue valve 2721 closed.FIG. 27B shows the support structure of FIG. 27A (2710) with tissuevalve 2721 attached to the structure of FIG. 33 (3310), which isdescribed in more detail below. Leaflets 2721 a, 2721 b, 2721 c may besuturelessly attached to the support structure 2710 along commissures2719 and along the distal portion of struts 2711. The suturelessattachments may be formed by sandwiching the leaflets within multi-plystruts making up struts 2711, 2719. More particularly, one side ofleaflet 2721 a may be sandwiched within multi-ply struts making upcommissure strut 2719-1 and the distal portion (the portion distal tojoint 2715-7) of longitudinal strut 2711-1; and the other side ofleaflet 2721 a may be sandwiched within multi-ply struts making upcommissure strut 2719-6 and the distal portion of longitudinal strut2711-12. One side of leaflet 2721 b may be suturelessly attached tocommissure strut 2719-5 (not shown) and the distal portion oflongitudinal strut 2711-9 (not shown); and the other side of leaflet2721 b may be suturelessly attached to commissure strut 2719-4 and thedistal portion of longitudinal strut 2711-8 (not shown). One side ofleaflet 2721 c may be sandwiched within multi-ply struts making upcommissure strut 2719-3 and the distal portion of longitudinal strut2711-5; and the other side of leaflet 2721 c may be suturelesslyattached to commissure strut 2719-2 and the distal portion oflongitudinal strut 2711-4.

In order to facilitate secure, suture-free leaflet attachment duringfabrication through sandwiching of the leaflets between the struts, theleaflets 2721 may comprise a shape as shown in FIG. 34 having a centralregion 3401 having a semicircular or paraboloid shape, with tworectangular tabs extending from each side of the central region 3401.The upper rectangular tabs 3403 may be sandwiched within multi-plystruts making up commissure struts 2719, and the lower rectangular tabs3405 may be sandwiched within multi-ply struts making up longitudinalstruts 2711. After the upper tabs 3403 and lower tabs 3405 aresandwiched between the struts, the portions of the tabs 3403, 3405 maybe removed, leaving the central region 3401 suturelessly attached to thesupport structure 2710. In another variation, the adjacent rectangulartabs 3403, 3405 may be attached to each other.

The support structure 2710 with attached leaflets 2721 a, 2721 b, 2721 cmay be collapsible and may be able to be reversibly expanded orcompressed by actuating the linkages to open or close the links. Whenradially inward pressure is applied to the longitudinal struts 2711, thesupport structure 2710 may collapse into a narrow profile.

FIG. 16 is a perspective view of the arrangement of strut members in aconical-shaped support structure configuration. In the conical structure10′, the strut members 11 may be arranged as shown in FIG. 2, exceptthat the middle scissor pivots may not bisect the struts. In particular,the middle scissor pivots (e.g. 15′-1, 15′-7) may divide the joinedstrut members (e.g. 11′-1, 11′-2 and 11′-3, 11′4) into unequal segmentsof 5/12 and 7/12 lengths. When fully assembled, the resulting supportstructure may thus conform to a conical shape when expanded. Forillustration purposes, the stent 10′ is shown with a single-threadedactuator rod 32′ (FIG. 6), but it is not a required element for thisstent embodiment.

The stent 10′ can also assume a cone shape in its expanded configurationby imposing a convex or concave curvature to the individual strutmembers 11 that comprise the stent 10′. This could be achieved by usinga material with memory, such as shape-memory or temperature sensitiveNitinol.

A valve can be orientated in the cone-shaped stent 10′ such that thebase of the valve was either in the narrower portion of the cone-shapedstent, with the nonbase portion of the valve in the wider portion of thecone. Alternatively, the base of the valve can be located in the widestportion of the stent with the non-base portion of the valve in theless-wide portion of the stent.

The orientation of a cone-shaped stent 10′ in the body can be eithertowards or away from the stream of blood flow. In other body lumens(e.g. respiratory tract or gastrointestinal tract), the stent could beorientated in either direction, in relationship to the axial plane.

FIG. 17 is a perspective view of an hourglass-shaped support structureconfiguration. In this configuration, the circumference around themiddle pivot points 15″-1, 15″-7, 15″-9 (the waist) may be less than thecircumference at either end of the stent 10″. As shown, the hourglassshaped support structure 10″ is achieved by reducing the number of strutmembers 11″ to six and shortening the strut members 11″ in comparison toprior embodiments. As a result of the shortening, there may be fewerorifices 13″ per strut member 11″. Because of the strut number andgeometry, each strut member 11″ may include a twist at points 19″ alongthere longitudinal planes. The twists may provide a flush interfacebetween joined strut 15″-3.

An hourglass stent configuration could also be achieved by imposingconcave or convex curvatures in individual bars 11″. The curvature couldbe a property of the materials (e.g. shape-memory or heat-sensitiveNitinol). The curvature could be absent in the compressed stent stateand appear when the stent is in its expanded state.

FIG. 29A is another expandable hourglass-shaped securing structureconfiguration. Hourglass structure 2910 may have a proximal opening2920, distal opening 2930, and a lumen 2940 therebetween (notindicated). Near the proximal opening 2920 the hourglass structure 2910may have a proximal tapered section 2950. Near the distal opening 2930the hourglass structure 2910 may have a distal tapered section 2960.Between the proximal tapered section 2950 and distal tapered section2960, near the longitudinal middle of the hourglass structure 2910, maybe a narrow section 2970 whose diameter may be smaller than thediameters of proximal tapered section 2950 and distal tapered section2960. As shown, the securing structure 2910 may include a plurality ofstrut members 2911 a, 2911 b interconnected by a plurality of pin joints2915. The strut members 2911 a, 2911 b may comprise a curved or helicalconfiguration that span the general length of the hourglass structure,wherein each strut may comprise a proximal and distal region with arelatively wider curvature, and a middle region with a relativelytighter curvature. The helical configuration of the struts may be rightor left-handed, as described in greater detail below. The curvatures ofthe proximal and distal region may or may not be the same. Inparticular, the pin joints 15 may allow the interconnected strut members2911 to rotate relative to each other. The pin joints may have an axisof rotation with a radial orientation. As shown there are six strutmembers 2911 a and six strut members 2911 b. However, in othervariations the hourglass structure 2910 may have other numbers of strutmembers. For instance, in one variation the hourglass structure 2910 mayhave three strut members 2911 a and three strut members 2911 b.

Hourglass structure 2910 may be configured such that it can act as asecuring body to be secured within a location within the body. Inparticular, structure 2910 can be configured to be placed near thelocation of the mitral valve in the heart, with the narrow section 2970in the location of the mitral valve opening, proximal tapered section2950 located in the left atrium, and distal tapered section 2960 locatedin the left ventricle. In a particular embodiment for implantation atthe mitral valve opening, the diameter at the narrow section 2970 may beabout 0.5-1.5 inches. More particularly, the diameter may be about 0.8inches. The diameter at the proximal tapered section 2950 may be about1-3 inches. More particularly, the diameter may be about 1.75 inches.The diameter at the distal tapered section 2960 may be about 1-3 inches.More particularly, the diameter may be about 1.75 inches. This hourglassconfiguration may allow the structure to be secured in the mitral valveopening without requiring a strong outward force to hold the structurein place.

As shown in FIG. 29A, deployment structure 3210 may also be attached tothe proximal and/or distal ends of the hourglass structure 2910. In thevariation in FIG. 29A, deployment structures 3210 may be connected toboth the proximal and distal ends of hourglass structure 2910, and theirends may deflect outward from the proximal and distal ends of hourglassstructure 2910. Deployment structure 3210 may comprise a serial chain ofscissor mechanisms comprising a plurality of longitudinal strut members3211 rotatably interconnected by a plurality of pin joints 2915. Asshown, there are twelve struts 3211. In another variation, hourglassstructure 2910 may not have deployment structures 3210 attached to itsproximal and distal ends. Hourglass structure 2910 may also have onlyone deployment structure 3210 that is attached to either its proximal ordistal end.

Strut members 2911 a, 2911 b and 3211 may be fabricated from a rigid orsemi-rigid biocompatible material as described elsewhere herein. In somevariations, strut members 3211 of deployment structure 3210 may befabricated from a biocompatible material having greater flexibility thanthe materials from which strut members 2911 a, 2911 b are fabricated.The greater flexibility may allow the deployment struts 3211 inwardlydeflectable. The dimensions of each strut can be chosen in accordancewith its desired use. As shown, each longitudinal strut member 2911 a,2911 b has a front surface 2511 f and a back surface 2511 b. In aparticular embodiment, each strut member may be made from stainlesssteel, which is about 0.001-0.100 inch thick. More particularly, eachstrut may be about 0.01 inch thick 300 series stainless steel. In othervariations, the deployment struts 3211 may be thinner than the struts2911 a, 2911 b, which may increase flexibility of the deployment struts3211. While all struts 2911 a, 2911 b and 3211 are shown as being ofuniform thickness, the thickness of a strut can vary across a strut,such as a gradual increase or decrease in thickness along the length ofa strut. Furthermore, individual struts 2911 a, 2911 b and 3211 candiffer in thickness from other individual struts 2911 a, 2911 b and 3211in the same support structure. In a particular embodiment, each strutmember 2911 a, 2911 b and 3211 may be about 0.01-0.25 inches wide. Moreparticularly, each strut 2911 a, 2911 b and 3211 may be about 0.06inches wide. While all struts 2911 a, 2911 b and 3211 are shown as beingof a uniform width, a strut can vary in width along its length.Furthermore, an individual strut 2911 a, 2911 b and 3211 can have adifferent width than another strut 2911 a, 2911 b and 3211 in the samesupport structure. The particular dimensions can be chosen based on theimplant site. The strut lengths can vary from strut to strut within thesame support structure, as is explained in detail below.

Each of strut members 2911 a, 2911 b may have a helical shape with thehelical axis aligned with the central axis of the securing structure2910. Strut members 2911 a may be right-handed helices, and strutmembers 2911 b may be left-handed helices. The diameter of the helicalshape may also vary along the length of the strut members such that thecircumferences at the longitudinal center of the strut members 2911 a,2911 b may be less than the circumferences at the proximal and distalends of the strut members 2911 a, 2911 b. The nonflatness or flatness ofthe struts can be a property of the material from which they areconstructed. For example, the struts can exhibit shape-memory orheat-responsive changes in shape to the struts during various states.Such states can be defined by the stent in the compressed or expandedconfiguration.

As shown, each strut member 3211 is bar shaped. The strut members canhowever be of different geometries. For example, instead of a uniformwidth, a strut 3211 can vary in width along its length. Furthermore, anindividual strut 3211 can have a different width than another strut inthe same deployment structure. Similarly, the strut lengths can varyfrom strut to strut within the same deployment structure. The particulardimensions can be chosen based on the implant site. Furthermore, thestruts 3211 can be non-flat structures. In particular, the struts 3211can include a curvature, such as in a concave, as in FIG. 29A, or convexmanner in relationship to the inner diameter of the deploymentstructure. The struts 3211 can also be twisted. The nonflatness orflatness of the struts 3211 can be a property of the material from whichthey are constructed. For example, the struts 3211 can exhibitshape-memory or heat-responsive changes in shape to the struts duringvarious states. Such states can be defined by the deployment structurein the compressed or expanded configuration.

Furthermore, the strut members 2911 a, 2911 b and 3211 can have a smoothor rough surface texture. In particular, a pitted surface can providetensile strength to the struts. In addition, roughness or pitting canprovide additional friction to help secure the support structure at theimplant site and encourage encapsulation of the securing structure 2910and deployment structure 3210 by tissue growth to further stabilize andsecuring structure 2910 at the implant site over time.

In certain instances, the securing structure 2910 and deploymentstructure 3210 could be comprised of struts that are multiple membersstacked upon one another. Within the same stent, some struts couldinclude elongated members stacked upon one another in a multi-plyconfiguration, and other struts could be one-ply, composed ofsingle-thickness members. Within a single strut, there can be areas ofone-ply and multi-ply layering of the members.

Each strut member 2911 a, 2911 b may also include a plurality oforifices 2913 spaced along the length of the strut member 2911 a or 2911b. On the front surface, the orifices may be countersunk 2917 to receivethe head of a fastener. In a particular embodiment, there may beseventeen equally spaced orifices 2913 along the length of each strutmember 2911 a, 2911 b, but more or fewer orifices can be used. Theorifices 2913 are shown as being of uniform diameter and uniform spacingalong the strut member 2911 a or 2911 b, but neither is required. FIG.29A shows deployment structure 3210 strut members 3211 as not havingorifices 2513 along their lengths. However, in other instances the strutmembers 3211 can have orifices 2513 along their lengths.

The strut members 2911 a, 2911 b may be arranged such that the helicalaxes of all strut members 2911 a, 2911 b are aligned and areinterconnected by rotatable pivot fasteners 2925, such as rivets,extending through aligned orifices 2913. It should be understood thatother rotatable fasteners 2925 can be employed such as screws, bolts,ball-in socket structures, nails, or eyelets, and that the fasteners canbe integrally formed in the struts 11 such as a peened semi-sphereinteracting with an indentation of orifice, or a male-female coupling.In addition to receiving a fastener, the orifices 2913 also provide anadditional pathway for tissue growth-over to stabilize and encapsulatethe securing structure 2910 over time.

As shown in FIG. 29A, each right-handed helical strut member 2911 a isan outer strut member. Each left-handed helical strut member 2911 b isan inner strut member. Each outer, right-handed individual strut member2911 a may be rotatably connected to an individual inner, left-handedstrut member 2911 b strut member, with their back surfaces in orientedtoward each other.

In particular, each outer, right-handed strut member 2911 a may berotatably connected to an inner, left-handed strut member 2911 b by adistal anchor pin joint 2915 by rivet 2925, located near the distal endsof the strut members 2911 a, 2911 b, and a proximal anchor pin joint2935 by rivet 2945, located near the proximal ends of the strut members2911 a, 2911 b. Each outer, right-handed strut member 2911 a may also berotatably connected to each of the five remaining inner, left-handedstrut members 2911 b via a scissor pin joint 2955.

More specifically, outer, right-handed strut member 2911 a-1 may berotatably connected to inner, left-handed strut member 2911 b-1 by adistal anchor pin joint 2915-1 by rivet 2925-1 (not shown), located nearthe distal ends of the strut members 2911 a-1, 2911 b-1. Outer,right-handed strut member 2911 a-1 may also be rotatably connected toinner, left-handed strut member 2911 b-1 by a proximal anchor pin joint2935-1 by rivet 2945-1 (not shown), located near the distal ends of thestrut members 2911 a-1, 2911 b-1.

In addition, proximal to pin joint 2915-1, outer, right-handed strutmember 2911 a-1 may be rotatably connected via scissor pin joint 2955 toinner, left-handed strut member 2911 b-6. Proximal to its connectionwith strut member 2911 b-6, strut member 2911 a-1 may be rotatablyconnected via scissor pin joint 2955 to inner, left-handed strut member2911 b-5. Proximal to its connection with strut member 2911 b-5, strutmember 2911 a-1 may be rotatably connected via scissor pin joint 2955 toinner, left-handed strut member 2911 b-4. Proximal to its connectionwith strut member 2911 b-4, strut member 2911 a-1 may be rotatablyconnected via scissor pin joint 2955 to inner, left-handed strut member2911 b-3. Proximal to its connection with strut member 2911 b-3, strutmember 2911 a-1 may be rotatably connected via scissor pin joint 2955 toinner, left-handed strut member 2911 b-2. Proximal to the connectionbetween strut members 2911 a-1 and 2911 b-2 may be the proximal anchorpin joint 2935-1. Each scissor pin joint 2955 described above may beseparated longitudinally from each other pin joint 2955 along strutmember 2911 a-1 by one open orifice 2913. Distal pin joint 2915-1 may beseparated longitudinally along strut member 2911 a-1 from the scissorpin joint between strut members 2911 a-1 and 2911 b-6 by three openorifices 2913. Proximal pin joint 2935-1 may be separated longitudinallyalong strut member 2911 a-1 from the scissor pin joint between strutmembers 2911 a-1 and 2911 b-2 by three open orifices 2913.

In addition, proximal to pin joint 2915-1, inner, left-handed strutmember 2911 b-1 may be rotatably connected via scissor pin joint 2955 toouter, right-handed strut member 2911 a-2. Proximal to its connectionwith strut member 2911 a-2, strut member 2911 b-1 may be rotatablyconnected via scissor pin joint 2955 to outer, right-handed strut member2911 a-3. Proximal to its connection with strut member 2911 a-3, strutmember 2911 b-1 may be rotatably connected via scissor pin joint 2955 toouter, right-handed strut member 2911 a-4. Proximal to its connectionwith strut member 2911 a-4, strut member 2911 b-1 may be rotatablyconnected via scissor pin joint 2955 to outer, right-handed strut member2911 a-5. Proximal to its connection with strut member 2911 a-5, strutmember 2911 b-1 may be rotatably connected via scissor pin joint 2955 toouter, right-handed strut member 2911 a-6. Proximal to the connectionbetween strut members 2911 b-1 and 2911 a-6 may be the proximal anchorpin joint 2935-1. Each scissor pin joint 2955 described above may beseparated longitudinally from each other pin joint 2955 along strutmember 2911 b-1 by one open orifice 2913. Distal pin joint 2915-1 may beseparated longitudinally along strut member 2911 b-1 from the scissorpin joint between strut members 2911 b-1 and 2911 a-2 by three openorifices 2913. Proximal pin joint 2935-1 may be separated longitudinallyalong strut member 2911 b-1 from the scissor pin joint between strutmembers 2911 b-1 and 2911 a-6 by three open orifices 2913. It should benoted that the spacings shown in FIG. 29A are not required; spacing maybe by more or fewer orifices.

Similar patterns of articulations exist between the remaining outer,right-handed strut members 2911 a and inner, left-handed strut members2911 b. More specifically, outer, right-handed strut member 2911 a-2 maybe rotatably connected to inner, left-handed strut member 2911 b-2 by adistal anchor pin joint 2915-2 by rivet 2925-2 (not shown), located nearthe distal ends of the strut members 2911 a-2, 2911 b-2. Outer,right-handed strut member 2911 a-2 may also be rotatably connected toinner, left-handed strut member 2911 b-2 by a proximal anchor pin joint2935-2 by rivet 2945-2 (not shown), located near the distal ends of thestrut members 2911 a-2, 2911 b-2.

In addition, proximal to pin joint 2915-2, outer, right-handed strutmember 2911 a-2 may be rotatably connected via scissor pin joint 2955 toinner, left-handed strut member 2911 b-1. Proximal to its connectionwith strut member 2911 b-1, strut member 2911 a-2 may be rotatablyconnected via scissor pin joint 2955 to inner, left-handed strut member2911 b-6. Proximal to its connection with strut member 2911 b-6, strutmember 2911 a-2 may be rotatably connected via scissor pin joint 2955 toinner, left-handed strut member 2911 b-5. Proximal to its connectionwith strut member 2911 b-5, strut member 2911 a-2 may be rotatablyconnected via scissor pin joint 2955 to inner, left-handed strut member2911 b-4. Proximal to its connection with strut member 2911 b-4, strutmember 2911 a-2 may be rotatably connected via scissor pin joint 2955 toinner, left-handed strut member 2911 b-3. Proximal to the connectionbetween strut members 2911 a-2 and 2911 b-3 may be the proximal anchorpin joint 2935-2. Each scissor pin joint 2955 described above may beseparated longitudinally from each other pin joint 2955 along strutmember 2911 a-2 by one open orifice 2913. Distal pin joint 2915-2 may beseparated longitudinally along strut member 2911 a-2 from the scissorpin joint between strut members 2911 a-2 and 2911 b-1 by three openorifices 2913. Proximal pin joint 2935-2 may be separated longitudinallyalong strut member 2911 a-2 from the scissor pin joint between strutmembers 2911 a-2 and 2911 b-3 by three open orifices 2913.

In addition, proximal to pin joint 2915-2, inner, left-handed strutmember 2911 b-2 may be rotatably connected via scissor pin joint 2955 toouter, right-handed strut member 2911 a-3. Proximal to its connectionwith strut member 2911 a-3, strut member 2911 b-2 may be rotatablyconnected via scissor pin joint 2955 to outer, right-handed strut member2911 a-4. Proximal to its connection with strut member 2911 a-4, strutmember 2911 b-2 may be rotatably connected via scissor pin joint 2955 toouter, right-handed strut member 2911 a-5. Proximal to its connectionwith strut member 2911 a-5, strut member 2911 b-2 may be rotatablyconnected via scissor pin joint 2955 to outer, right-handed strut member2911 a-6. Proximal to its connection with strut member 2911 a-6, strutmember 2911 b-2 may be rotatably connected via scissor pin joint 2955 toouter, right-handed strut member 2911 a-1. Proximal to the connectionbetween strut members 2911 b-2 and 2911 a-1 may be the proximal anchorpin joint 2935-2. Each scissor pin joint 2955 described above may beseparated longitudinally from each other pin joint 2955 along strutmember 2911 b-2 by one open orifice 2913. Distal pin joint 2915-2 may beseparated longitudinally along strut member 2911 b-2 from the scissorpin joint between strut members 2911 b-2 and 2911 a-3 by three openorifices 2913. Proximal pin joint 2935-2 may be separated longitudinallyalong strut member 2911 b-2 from the scissor pin joint between strutmembers 2911 b-2 and 2911 a-1 by three open orifices 2913. It should benoted that the spacings shown in FIG. 29A are not required; spacing maybe by more or fewer orifices.

Outer, right-handed strut member 2911 a-3 may be rotatably connected toinner, left-handed strut member 2911 b-3 by a distal anchor pin joint2915-3 by rivet 2925-3 (not shown), located near the distal ends of thestrut members 2911 a-3, 2911 b-3. Outer, right-handed strut member 2911a-3 may also be rotatably connected to inner, left-handed strut member2911 b-3 by a proximal anchor pin joint 2935-3 by rivet 2945-3 (notshown), located near the distal ends of the strut members 2911 a-3, 2911b-3.

In addition, proximal to pin joint 2915-3, outer, right-handed strutmember 2911 a-3 may be rotatably connected via scissor pin joint 2955 toinner, left-handed strut member 2911 b-2. Proximal to its connectionwith strut member 2911 b-2, strut member 2911 a-3 may be rotatablyconnected via scissor pin joint 2955 to inner, left-handed strut member2911 b-1. Proximal to its connection with strut member 2911 b-1, strutmember 2911 a-3 may be rotatably connected via scissor pin joint 2955 toinner, left-handed strut member 2911 b-6. Proximal to its connectionwith strut member 2911 b-6, strut member 2911 a-3 may be rotatablyconnected via scissor pin joint 2955 to inner, left-handed strut member2911 b-5. Proximal to its connection with strut member 2911 b-5, strutmember 2911 a-3 may be rotatably connected via scissor pin joint 2955 toinner, left-handed strut member 2911 b-4. Proximal to the connectionbetween strut members 2911 a-3 and 2911 b-4 may be the proximal anchorpin joint 2935-3. Each scissor pin joint 2955 described above may beseparated longitudinally from each other pin joint 2955 along strutmember 2911 a-3 by one open orifice 2913. Distal pin joint 2915-3 may beseparated longitudinally along strut member 2911 a-3 from the scissorpin joint between strut members 2911 a-3 and 2911 b-2 by three openorifices 2913. Proximal pin joint 2935-3 may be separated longitudinallyalong strut member 2911 a-3 from the scissor pin joint between strutmembers 2911 a-3 and 2911 b-4 by three open orifices 2913.

In addition, proximal to pin joint 2915-3, inner, left-handed strutmember 2911 b-3 may be rotatably connected via scissor pin joint 2955 toouter, right-handed strut member 2911 a-4. Proximal to its connectionwith strut member 2911 a-4, strut member 2911 b-3 may be rotatablyconnected via scissor pin joint 2955 to outer, right-handed strut member2911 a-5. Proximal to its connection with strut member 2911 a-5, strutmember 2911 b-3 may be rotatably connected via scissor pin joint 2955 toouter, right-handed strut member 2911 a-6. Proximal to its connectionwith strut member 2911 a-6, strut member 2911 b-3 may be rotatablyconnected via scissor pin joint 2955 to outer, right-handed strut member2911 a-1. Proximal to its connection with strut member 2911 a-1, strutmember 2911 b-3 may be rotatably connected via scissor pin joint 2955 toouter, right-handed strut member 2911 a-2. Proximal to the connectionbetween strut members 2911 b-3 and 2911 a-2 may be the proximal anchorpin joint 2935-3. Each scissor pin joint 2955 described above may beseparated longitudinally from each other pin joint 2955 along strutmember 2911 b-3 by one open orifice 2913. Distal pin joint 2915-3 may beseparated longitudinally along strut member 2911 b-3 from the scissorpin joint between strut members 2911 b-3 and 2911 a-4 by three openorifices 2913. Proximal pin joint 2935-3 may be separated longitudinallyalong strut member 2911 b-3 from the scissor pin joint between strutmembers 2911 b-3 and 2911 a-2 by three open orifices 2913. It should benoted that the spacings shown in FIG. 29A are not required; spacing maybe by more or fewer orifices.

Outer, right-handed strut member 2911 a-4 may be rotatably connected toinner, left-handed strut member 2911 b-4 by a distal anchor pin joint2915-4 by rivet 2925-4 (not shown), located near the distal ends of thestrut members 2911 a-4, 2911 b-4. Outer, right-handed strut member 2911a-4 may also be rotatably connected to inner, left-handed strut member2911 b-4 by a proximal anchor pin joint 2935-4 by rivet 2945-4 (notshown), located near the distal ends of the strut members 2911 a-4, 2911b-4.

In addition, proximal to pin joint 2915-4, outer, right-handed strutmember 2911 a-4 may be rotatably connected via scissor pin joint 2955 toinner, left-handed strut member 2911 b-3. Proximal to its connectionwith strut member 2911 b-3, strut member 2911 a-4 may be rotatablyconnected via scissor pin joint 2955 to inner, left-handed strut member2911 b-2. Proximal to its connection with strut member 2911 b-2, strutmember 2911 a-4 may be rotatably connected via scissor pin joint 2955 toinner, left-handed strut member 2911 b-1. Proximal to its connectionwith strut member 2911 b-1, strut member 2911 a-4 may be rotatablyconnected via scissor pin joint 2955 to inner, left-handed strut member2911 b-6. Proximal to its connection with strut member 2911 b-6, strutmember 2911 a-4 may be rotatably connected via scissor pin joint 2955 toinner, left-handed strut member 2911 b-5. Proximal to the connectionbetween strut members 2911 a-4 and 2911 b-5 may be the proximal anchorpin joint 2935-4. Each scissor pin joint 2955 described above may beseparated longitudinally from each other pin joint 2955 along strutmember 2911 a-4 by one open orifice 2913. Distal pin joint 2915-4 may beseparated longitudinally along strut member 2911 a-4 from the scissorpin joint between strut members 2911 a-4 and 2911 b-3 by three openorifices 2913. Proximal pin joint 2935-4 may be separated longitudinallyalong strut member 2911 a-4 from the scissor pin joint between strutmembers 2911 a-4 and 2911 b-5 by three open orifices 2913.

In addition, proximal to pin joint 2915-4, inner, left-handed strutmember 2911 b-4 may be rotatably connected via scissor pin joint 2955 toouter, right-handed strut member 2911 a-5. Proximal to its connectionwith strut member 2911 a-5, strut member 2911 b-4 may be rotatablyconnected via scissor pin joint 2955 to outer, right-handed strut member2911 a-6. Proximal to its connection with strut member 2911 a-6, strutmember 2911 b-4 may be rotatably connected via scissor pin joint 2955 toouter, right-handed strut member 2911 a-1. Proximal to its connectionwith strut member 2911 a-1, strut member 2911 b-4 may be rotatablyconnected via scissor pin joint 2955 to outer, right-handed strut member2911 a-2. Proximal to its connection with strut member 2911 a-2, strutmember 2911 b-4 may be rotatably connected via scissor pin joint 2955 toouter, right-handed strut member 2911 a-3. Proximal to the connectionbetween strut members 2911 b-4 and 2911 a-3 may be the proximal anchorpin joint 2935-4. Each scissor pin joint 2955 described above may beseparated longitudinally from each other pin joint 2955 along strutmember 2911 b-4 by one open orifice 2913. Distal pin joint 2915-4 may beseparated longitudinally along strut member 2911 b-4 from the scissorpin joint between strut members 2911 b-4 and 2911 a-5 by three openorifices 2913. Proximal pin joint 2935-4 may be separated longitudinallyalong strut member 2911 b-4 from the scissor pin joint between strutmembers 2911 b-4 and 2911 a-3 by three open orifices 2913. It should benoted that the spacings shown in FIG. 29A are not required; spacing maybe by more or fewer orifices.

Outer, right-handed strut member 2911 a-5 may be rotatably connected toinner, left-handed strut member 2911 b-5 by a distal anchor pin joint2915-5 by rivet 2925-5 (not shown), located near the distal ends of thestrut members 2911 a-5, 2911 b-5. Outer, right-handed strut member 2911a-5 may be also rotatably connected to inner, left-handed strut member2911 b-5 by a proximal anchor pin joint 2935-5 by rivet 2945-5 (notshown), located near the distal ends of the strut members 2911 a-5, 2911b-5.

In addition, proximal to pin joint 2915-5, outer, right-handed strutmember 2911 a-5 may be rotatably connected via scissor pin joint 2955 toinner, left-handed strut member 2911 b-4. Proximal to its connectionwith strut member 2911 b-4, strut member 2911 a-5 may be rotatablyconnected via scissor pin joint 2955 to inner, left-handed strut member2911 b-3. Proximal to its connection with strut member 2911 b-3, strutmember 2911 a-5 may be rotatably connected via scissor pin joint 2955 toinner, left-handed strut member 2911 b-2. Proximal to its connectionwith strut member 2911 b-2, strut member 2911 a-5 may be rotatablyconnected via scissor pin joint 2955 to inner, left-handed strut member2911 b-1. Proximal to its connection with strut member 2911 b-1, strutmember 2911 a-5 may be rotatably connected via scissor pin joint 2955 toinner, left-handed strut member 2911 b-6. Proximal to the connectionbetween strut members 2911 a-5 and 2911 b-6 may be the proximal anchorpin joint 2935-5. Each scissor pin joint 2955 described above may beseparated longitudinally from each other pin joint 2955 along strutmember 2911 a-5 by one open orifice 2913. Distal pin joint 2915-5 may beseparated longitudinally along strut member 2911 a-5 from the scissorpin joint between strut members 2911 a-5 and 2911 b-4 by three openorifices 2913. Proximal pin joint 2935-5 may be separated longitudinallyalong strut member 2911 a-5 from the scissor pin joint between strutmembers 2911 a-5 and 2911 b-6 by three open orifices 2913.

In addition, proximal to pin joint 2915-5, inner, left-handed strutmember 2911 b-5 may be rotatably connected via scissor pin joint 2955 toouter, right-handed strut member 2911 a-6. Proximal to its connectionwith strut member 2911 a-6, strut member 2911 b-5 may be rotatablyconnected via scissor pin joint 2955 to outer, right-handed strut member2911 a-1. Proximal to its connection with strut member 2911 a-1, strutmember 2911 b-5 may be rotatably connected via scissor pin joint 2955 toouter, right-handed strut member 2911 a-2. Proximal to its connectionwith strut member 2911 a-2, strut member 2911 b-5 may be rotatablyconnected via scissor pin joint 2955 to outer, right-handed strut member2911 a-3. Proximal to its connection with strut member 2911 a-3, strutmember 2911 b-5 may be rotatably connected via scissor pin joint 2955 toouter, right-handed strut member 2911 a-4. Proximal to the connectionbetween strut members 2911 b-5 and 2911 a-4 may be the proximal anchorpin joint 2935-5. Each scissor pin joint 2955 described above may beseparated longitudinally from each other pin joint 2955 along strutmember 2911 b-5 by one open orifice 2913. Distal pin joint 2915-5 may beseparated longitudinally along strut member 2911 b-5 from the scissorpin joint between strut members 2911 b-5 and 2911 a-6 by three openorifices 2913. Proximal pin joint 2935-5 may be separated longitudinallyalong strut member 2911 b-5 from the scissor pin joint between strutmembers 2911 b-5 and 2911 a-4 by three open orifices 2913. It should benoted that the spacings shown in FIG. 29A are not required; spacing maybe by more or fewer orifices.

Outer, right-handed strut member 2911 a-6 may be rotatably connected toinner, left-handed strut member 2911 b-6 by a distal anchor pin joint2915-6 by rivet 2925-6 (not shown), located near the distal ends of thestrut members 2911 a-6, 2911 b-6. Outer, right-handed strut member 2911a-6 may also be rotatably connected to inner, left-handed strut member2911 b-6 by a proximal anchor pin joint 2935-6 by rivet 2945-6 (notshown), located near the distal ends of the strut members 2911 a-6, 2911b-6.

In addition, proximal to pin joint 2915-6, outer, right-handed strutmember 2911 a-6 may be rotatably connected via scissor pin joint 2955 toinner, left-handed strut member 2911 b-5. Proximal to its connectionwith strut member 2911 b-5, strut member 2911 a-6 may be rotatablyconnected via scissor pin joint 2955 to inner, left-handed strut member2911 b-4. Proximal to its connection with strut member 2911 b-4, strutmember 2911 a-6 may be rotatably connected via scissor pin joint 2955 toinner, left-handed strut member 2911 b-3. Proximal to its connectionwith strut member 2911 b-3, strut member 2911 a-6 may be rotatablyconnected via scissor pin joint 2955 to inner, left-handed strut member2911 b-2. Proximal to its connection with strut member 2911 b-2, strutmember 2911 a-6 may be rotatably connected via scissor pin joint 2955 toinner, left-handed strut member 2911 b-1. Proximal to the connectionbetween strut members 2911 a-6 and 2911 b-1 may be the proximal anchorpin joint 2935-6. Each scissor pin joint 2955 described above may beseparated longitudinally from each other pin joint 2955 along strutmember 2911 a-6 by one open orifice 2913. Distal pin joint 2915-6 may beseparated longitudinally along strut member 2911 a-6 from the scissorpin joint between strut members 2911 a-6 and 2911 b-5 by three openorifices 2913. Proximal pin joint 2935-6 may be separated longitudinallyalong strut member 2911 a-6 from the scissor pin joint between strutmembers 2911 a-6 and 2911 b-1 by three open orifices 2913.

In addition, proximal to pin joint 2915-6, inner, left-handed strutmember 2911 b-6 may be rotatably connected via scissor pin joint 2955 toouter, right-handed strut member 2911 a-1. Proximal to its connectionwith strut member 2911 a-1, strut member 2911 b-6 may be rotatablyconnected via scissor pin joint 2955 to outer, right-handed strut member2911 a-2. Proximal to its connection with strut member 2911 a-2, strutmember 2911 b-6 may be rotatably connected via scissor pin joint 2955 toouter, right-handed strut member 2911 a-3. Proximal to its connectionwith strut member 2911 a-3, strut member 2911 b-6 may be rotatablyconnected via scissor pin joint 2955 to outer, right-handed strut member2911 a-4. Proximal to its connection with strut member 2911 a-4, strutmember 2911 b-6 may be rotatably connected via scissor pin joint 2955 toouter, right-handed strut member 2911 a-5. Proximal to the connectionbetween strut members 2911 b-6 and 2911 a-5 may be the proximal anchorpin joint 2935-6. Each scissor pin joint 2955 described above may beseparated longitudinally from each other pin joint 2955 along strutmember 2911 b-6 by one open orifice 2913. Distal pin joint 2915-6 may beseparated longitudinally along strut member 2911 b-6 from the scissorpin joint between strut members 2911 b-6 and 2911 a-1 by three openorifices 2913. Proximal pin joint 2935-6 may be separated longitudinallyalong strut member 2911 b-6 from the scissor pin joint between strutmembers 2911 b-6 and 2911 a-5 by three open orifices 2913. It should benoted that the spacings shown in FIG. 29A are not required; spacing maybe by more or fewer orifices.

Strut members 3211 of deployment structures 3210 are arranged as a chainof four-bar linkages. The strut members 3211 are rotatablyinterconnected at joints 3215 by rotatable pivot fasteners 3225, such asrivets. It should be understood that other rotatable fasteners 3225 canbe employed such as screws, bolts, ball-in-socket structures, nails, oreyelets, and that the fasteners can be integrally formed in the struts3211 such as a peened semi-sphere interacting with an indentation ororifice, or a male-female coupling.

In each four-bar linkage, two outer strut members 3211 may overlap twoinner strut members 3211, with their back surfaces in communication witheach other. In particular, first strut member 3211-1 may be rotatablyconnected to the second strut member 3211-2 by a middle pin joint 3215using rivet 3225 that bisects the strut members 3211-1, 3211-2.Similarly, the third strut member 3211-3 may be rotatably connected tobisect the four strut member 3211-4 by a middle pin joint 3215 usingrivet 3225. As shown, the resulting scissor arms are of equal length. Itshould also be understood that the scissor arms may be of unequallength.

The second strut member 3211-2 may also be rotatably connected to thethird strut member 3211-3 by a distal anchor pin joint 3215, locatednear the distal ends of the strut members 3211-2, 3211-3. Similarly, thefirst strut member 3211-1 may be rotatably connected to the fourth strutmember 3211-4 by a proximal anchor pin joint 3215 located near theproximal ends of the strut members 3211-1, 3211-4. The curved shape ofstruts 3211 may reduce the stresses on the anchor rivets 3225 byproviding a flush interface between the joined struts.

As can be seen, the deployment structure 3210 may be fabricated bylinking together a serial chain of scissor mechanisms. The chain maythen be wrapped to join the last scissor mechanism with the firstscissor mechanism in the chain. The diameter of deployment structure3210 may be approximately the same as the diameter of the proximaltapered section 2950 of hourglass structure 2910 or the distal taperedsection 2960 of hourglass structure 2910. The deployment structure 3210may be rotatably attached to the hourglass structure 2910 at the distalor proximal anchor pin joints 3215 of deployment structure 3210 and theproximal anchor pin joints 2935 or distal anchor pin joints 2915 ofhourglass structure 2910. In another embodiment, the strut members 3211of deployment structure 3210 may extend along the distal and proximalstrut portions of helical struts 2911 of hourglass securing structure2910, overlapping with the distal and proximal portions of helicalstruts 2911. In such an embodiment, the overlapping of the strut members3211 with the distal and proximal portions of helical struts 2911 mayallow greater flexibility in the deployment structure.

The hourglass structure 2910 can be expanded or compressed by actuatingthe linkages to open or close the links. The deployment structure 3210can also be expanded or compressed by actuating the linkages to open orclose the links. When deployment structure 3210 is attached to hourglassstructure 2910, the attachment may be such that by actuating thelinkages on either hourglass structure 2910 or deployment structure3210, the combination is expanded or compressed.

An alternative embodiment of a securing structure is shown in FIG. 33.In this embodiment 3310, six curved struts may be joined into threeinterconnected leaflets to form a structure which may have, like thesecuring structure of FIG. 29A, an hourglass shape such that a middlesection 3370 has a narrower diameter than the distal and proximalsections and may be configured to be attached to a valve supportstructure, and a distal section 3360 and a proximal section 3350 withlarger diameters configured to hold the securing structure 3310 inplace. The embodiment of FIG. 33 may be dimensioned to be secured in theaortic valve opening. In one embodiment, the diameter at the proximaland distal sections 3350, 3360 may be about 1-3 inches. Moreparticularly, the diameter may be about 2 inches. The diameter at thenarrow section 3370 may be about 0.5-2.0 inches. More particularly, thediameter may be about 1 inch.

The embodiment shown in FIG. 33 may be made up of six curved struts,which may have a helical shape. The struts may comprise threeright-handed helical struts 3311 a, and three left-handed helical struts3311 b. Each of the three right-handed helical struts 3311 a may beconnected at both its distal and proximal ends to the same left-handedstrut 3311 b, at proximal pivot joint 3335 and distal pivot joint 3315,forming three pairs of struts, each pair forming a curved leaflet shape.Each of the three right-handed helical struts 3311 a may also beconnected to the two remaining left-handed helical struts 3311 b at twomiddle pivot joints 3355. As shown, there are two open orifices 3313between the proximal pivot joint and the proximal-most middle joint; twoopen orifices 3313 between the distal pivot joint and the distal-mostmiddle joint; and one open orifice between the two middle pivot joints,but in other variations there may be other numbers of orifices or noorifices.

It should be noted that any of the above-described support structurescan be extended beyond the anchor joints at either of both ends of thestent. By coupling a series of stents in an end-to-end chain fashion,additional stent lengths and geometries can be fabricated. Inparticular, an hourglass-shaped stent could be achieved by joining twocone-shaped stents at their narrow ends. The hourglass shape can also bemodified by assembling the middle scissor pivots off center as shown inFIG. 14.

Certain variations of the above-described support structures can also becombined. FIGS. 31A-E show one combination, which may include variationsof hourglass structure 2910 (FIG. 29A), deployment structures 3210, avalve support structure 2710 (FIG. 27A), and two support structures 3010(FIG. 30) that act as opposing self-locking rings. In this combinationstructure, the central axes of the hourglass structure 2910, valvesupport structure 2710, and support structures 3010 may be aligned.Valve support structure 2710 may be secured to hourglass structure 2910near the longitudinal center of hourglass structure 2910 within thelumen 2940 of hourglass structure 2910. The narrow section 2970 ofhourglass structure 2910 may have a circumference configured tocircumscribe the valve securing structure 2910. Support structures 3010may be secured to hourglass structure 2910 within the lumen 2940 ofhourglass structure 2910. One support structure 3010 may be secured nearproximal tapered section 2950 and one support structure 3010 may besecured near distal tapered section 2960 of hourglass structure 2910. Asshown in FIGS. 31A-E, the combination structure may be dimensioned forcatheter delivery. In one embodiment, the total length of thecombination structure may be about 5-20 cm in length. In anotherembodiment, the total length of the combination structure may be about6-16 cm in length. In another embodiment, the total length of thecombination structure may be about 8-14 cm in length.

In another embodiment, shown in FIG. 29B without valve support structure2710, support structures 3010 may be secured to hourglass structure 2910such that the proximal joints 2935 of hourglass structure 2910 arerotatably connected to distal joints 3215 of support structure 3010, andthe distal joints 2915 of hourglass structure 2910 are rotatablyconnected to the proximal joints 3215 of a second support structure3010. Thus, rather than the support structures 3010 being placed withinthe length of hourglass structure 2910 as in the embodiment shown inFIG. 29A, the support structures 3010 in the embodiment shown in FIG.29B may be located beyond the length of the hourglass structure 2910. Inthe embodiment shown in FIG. 29B, one deployment structure 3210 may beattached each of the two support structures 3010. As shown, the strutmembers 3211 of deployment structure 3210 may overlap with the strutmembers 3011 of support structure 3010 from the outermost joint 3215 tothe middle pin joint 3215. The overlap between strut members 3211 and3011 may allow greater flexibility in the deployment structure. Thecombination structures may have other properties that allow for greaterflexibility in the deployment structure. For example, as shown in FIG.29B, hourglass structure 2910 may not have all the segments of helicalstruts 2911 that are shown in FIG. 29A. In the embodiment shown in FIG.29B, the hourglass structure 2910 may not contain the portion of outer,right-handed strut member 2911 a-1 extending from the distal anchor pinjoint 2915-1 to the scissor pin joint connection 2955 with inner,left-handed strut member 2911 b-6; and the hourglass structure 2910 maynot contain the portion of inner, left-handed strut member 2911 b-1extending from the distal anchor pin joint 2915-1 to the scissor pinjoint connection 2955 with outer, right-handed strut member 2511 a-2.The omission of these segments of the helical struts may allow greaterflexibility in the deployment structure. In other embodiments, inaddition or alternatively, other segments of the helical struts may alsobe omitted.

The combination structure may also include attachment rings 3111 securedto proximal pin joints 2915 of proximal deployment structure 3210 anddistal pin joints 2915 of distal deployment structure 3210, as shown inFIG. 31G. The attachment rings 3111 may be secured to proximal pinjoints 2915 by loops, wherein both ends of the loops may be attached tothe proximal joints 2915. The attachment rings 3111 may be secured todistal pin joints 2915 by loops, wherein both ends of the loops may beattached to the distal joints 2915. In one embodiment, the loops may beformed from a flat bar-shaped member having a rectangular cross-sectionfolded to create a loop, and the attachment rings 3111 may be formedfrom a wire having a circular cross-section wrapped into a ring shape,and the cross-sectional area of the wire may be smaller than thecross-sectional area of the bar-shaped member. The attachment rings 3111can spin and rotate freely within the loops.

The combination structure may also include one or more skirts. The skirtmay be a thin layer of material that lines the structure. The skirtmaterial can be pericardial tissue, polyester, PTFE, or other materialor combinations of materials suitable for accepting tissue in growth,including chemically treated materials to promote tissue growth orinhibit infection. The skirt may function to reduce or eliminate leakagearound the valve, or “paravalvular leak,” and in particular, may haveincreased sealing when greater pressure is applied to the skirt. In someembodiments, there may be a skirt at the proximal tapered section 2950of hourglass structure 2910 and at the distal tapered section 2960 ofhourglass structure 2910. In other embodiments, for example the oneshown in FIG. 35A (shown without valve support structure 2710), theremay be a skirt 3501 at the proximal tapered section 2950 of hourglassstructure 2910, a skirt 3503 at the distal tapered section 2960 ofhourglass structure 2910, and a skirt 3505 at the narrow section 2970 ofhourglass structure 2910. In some embodiments, skits 3501, 3503, 3505may be contiguous with each other; in other embodiments, kits 3501,3503, 3505 may be separate. In some embodiments, the skirt elements maybe located on the outside of the hourglass structure; in otherembodiments, the skirt elements may be located on the inside of thehourglass structure. In other embodiments, the skirt elements may besandwiched between multi-ply struts in the hourglass structure. In someembodiments, the skirt material may line the full circumference of theproximal tapered section 2950, distal tapered section 2960, and narrowsection 2970 of hourglass structure 2910, as shown in FIG. 35A.

In other embodiments, the skirt may line only a portion of the fullcircumference of the proximal tapered section 2950, distal taperedsection 2960, and narrow section 2970 of hourglass structure 2910. Forexample, as shown in FIG. 35D, the skirt 3503 lining the distal taperedsection 2960 may contain an opening 3507 to preserve an aortic outflowtract. FIG. 35D shows a combination structure, including tissue valve3509, implanted in the mitral opening from a ventricular view. In theembodiment in FIG. 35D, the opening 3507 in the skirt materialcorresponds with an open region in the support structure (i.e. a regionwithout a strut), which in turn corresponds with the aortic outflowtract. FIG. 35E is an atrial view of the same structure implanted in themitral opening, showing the proximal end of the same embodiment. Asshown in FIG. 35E, the skirt 3501 lining the proximal tapered section2950 may line the full circumference of the proximal tapered section2950. In other embodiments, the skirt may be made up of severalseparate, non-contiguous regions. For example, FIG. 35B shows anembodiment of the combination structure of FIG. 27B, having a securingstructure 3310 connected to a valve support structure 2710. The skirt inthe embodiment in FIG. 35B has six separate regions 3501 a, 3501 b, 3501c, 3503 a, 3503 b, 3503 c. The skirt regions 3503 a, 3503 b, 3503 c areattached to the upper portion of each of the three the leaflets in theportion extending above the valve support structure 2710. The skirtregions 3501 a, 3501 b, 3501 c are attached to the upper portions ofeach of the three leaflets in the portion extending below the valvesupport structure 2710. In some variations, such as the one shown inFIG. 35B, the skirt material may extend approximately 75-95% toward thedistal joint between the two struts forming each leaflet. In othervariations, the skirt regions may be smaller. For example, in theembodiment in FIG. 35C, the skirt material may extend approximately40-60% toward the distal joint between the two struts forming eachleaflet.

Although FIGS. 31A to 31E illustrate one combination of the structures,the structures described here can be used in other combinations, orother variations of these structures can be combined. For instance, acombination may include variations of hourglass structure 2910 (FIG.29A), two deployment structures 3210 (FIG. 29A), valve support structure2510 (FIG. 25) and prosthetic valve 121, and/or two support structures10 (FIG. 1). Another combination may include the hourglass securingsupport structure 3310 of FIG. 33, a variation of the valve supportstructure 2510 (FIG. 27A) dimensioned for placement in the aortic valveopening, and/or a prosthetic valve 121. In another variation, acombination may have other locking mechanisms instead of supportstructure 3010 that act as locking rings. For instance, the lockingmechanism may be a drive screw, a shim axially interwoven between theinner and outer struts of hourglass structure 2910, or a plug placedinto one of the cells formed by the struts in the combination structure.

The combination can be reversibly expanded and compressed. Thestructures 2910, 2710, 3210, and 3010 can be secured and aligned suchthat by actuating the linkages on one of the four structures, the entirecombination of four structures is expanded or compressed. Thecombination can be locked by expanding it into a fully expanded state,wherein support structure 3010 enters a locked state such that radiallyinward pressure does not cause the support structure 3010 tore-compress. Having support structure 3010 in a locked state can alsoprevent further movement of the combination. The combination orindividual structures may also be locked in a fully expanded statethrough other means. For instance, in one variation the supportstructure of FIG. 27A (2710) may enter a locked state when it enters afully expanded state, wherein radially inward pressure does not causethe support structure 2710 to re-compress. Once in a locked state, thehourglass configuration may allow the structure to be secure din themitral valve opening without requiring a strong outward force to holdthe structure in place.

A surgeon can expand or compress the combination from a location remotefrom the implant site using an actuation mechanism. The actuatormechanism can exert force to expand the combination diameter by eitherincreasing the distance between neighboring scissor joints, ordecreasing the distance between the anchor joints in any one of thestructures in the combination. In one variation, the actuator mechanismcan be the same as actuator mechanism 30 described in detail above. Onecontrol catheter assembly 40 usable with the actuator mechanism isdescribed in detail above.

FIGS. 31F-I show the combination of FIGS. 31A-E with control catheterassembly 3140. Control catheter assembly 3140 can be dimensioned to beinserted with the combination structure through a biological lumen, suchas a human artery. As shown in FIG. 32, the control catheter assembly3140 has a flexible outer sheath 3148 encasing four nested catheters.One nested catheter may have L-shaped hooks 3112 a, wherein the open endof the hook may be proximally facing. Another nested catheter may haveL-shaped hooks 3112 b, wherein the open end of the hook may be distallyfacing. The distally facing hooks may be located distal to theproximally facing hooks. The L-shaped hooks 3112 may be configured suchthat the attachment rings 3111 can be looped around the hooks 3112.Another nested catheter may have attached end cap 3113 a, wherein theend cap's opening may be distally facing and may be configured to fitover the ends of the proximally facing L-shaped hooks 3112 a. Anothernested catheter may have attached end cap 3113 b, wherein the end cap'sopening may be proximally facing and may be configured to fit over theends of the distally facing L-shaped hooks 3112 b. The end caps 3113 maybe configured such that if attachment rings 3111 are looped around hooks3112, placing the end caps over the L-shaped hooks 3112 may secure theattachment rings 3111 over the hooks 3112. Each of the four nestedcatheters may be independently moveable relative to the others, or thefour catheters may be able to be moved concertedly. The proximal ends ofthe catheters may contain screw locks to allow for concerted movement.In particular, in one embodiment the catheter comprising end cap 3113 amay be able to be screw-locked to the catheter comprising hooks 3112 a;and the catheter comprising end cap 3113 b may be able to bescrew-locked to the catheter comprising hooks 3112 b. In anotherembodiment, all four catheters can be configured to screw-lockedtogether. In another embodiment, hooks 3112 can have other shapes.

The combination structure shown in FIGS. 31A-I or other combinations canbe attached to the control catheter assembly by looping the attachmentrings 3111 on the distal end of the deployment structure 3210 over thedistally facing L-shaped hooks 3112 b and securing the attachment ringsto the hooks using the end caps 3113 b; and looping the attachment rings3111 on the proximal end of the combination structure over theproximally facing L-shaped hooks 3112 a and securing the attachmentrings to the hooks using the end caps 3113 a. In another embodiment, thecombination structure can be attached to the control catheter assemblyby looping the attachment rings 3111 on the proximal end of thecombination structure over the distally facing L-shaped hooks 3112 b andsecuring the attachment rings to the hooks using the end caps 3113 b;and looping the attachment rings 3111 on the distal end of thecombination structure over the proximally facing L-shaped hooks 3112 aand securing the attachment rings to the hooks using the end caps 3113a. When the attachment rings 3111 are secured to the control catheterassembly, the deployment struts 3211 of deployment structure 3210 arecentrally deflected to allow attachment to the catheter controlassembly.

The orientation in which the combination structure is attached to thecontrol catheter assembly may depend on the method of delivery. In oneembodiment, the combination structure may comprise a prosthetic mitralvalve and may be delivered through the femoral artery; in anotherembodiment, a combination structure may comprise a prosthetic aorticvalve and may be delivered through the femoral artery. In suchembodiments the proximal end of the combination structure may beattached to the proximally facing L-shaped hooks 3112 a. In anotherembodiment, the combination structure may comprise a prosthetic mitralvalve and may be delivered transseptally, either through the superiorvena cava or through the inferior vena cava; in another embodiment, acombination structure may comprise a prosthetic aortic valve and may bedelivered transseptally, either through the superior vena cava orthrough the inferior vena cava; in such embodiments the proximal end ofthe combination structure may be attached to the proximally facingL-shaped hooks 3112 a. In another embodiment the combination structuremay comprise a prosthetic mitral valve and may be deliveredtransapically; in another embodiment, a combination structure maycomprise a prosthetic aortic valve and may be delivered transapically;in such embodiments the proximal end of the combination structure may beattached to the distally facing L-shaped hooks 3112 b.

The combination structure shown in FIGS. 31A-I and other combinationstructures may be encased in a flexible sheath during insertion anddelivery. The sheath may be removed before or during use of the actuatormechanism to expand the diameter. In one variation, the sheath isremoved during the expansion of the diameter, and as a result, thedistal portion of the combination structure no longer covered by thesheath may expand, while the proximal portion of the combinationstructure still covered by the sheath may remain compressed until thesheath is fully removed.

The combination structure shown in FIGS. 31A-I and other combinationstructures may be highly flexible. Flexibility may be desirable duringdelivery of the structure, particularly in an embodiment in which thestructure is delivered transseptally. In some instances, the flexibilityof the combination structure may be varied by varying the spacingbetween strut members. More particularly, the flexibility may be able tobe increased by increasing the spacing between strut members and/orincreasing the longitudinal distance along strut members between joints.

The combination structure may be able to be expanded and compressed bymoving the catheters to change the distance between distally-facingL-shaped hooks 3112 b and proximally-facing L-shaped hooks 3112 a. Shownin collapsed state in FIG. 31I, the distance between the distally-facingL-shaped hooks 3112 b and proximally-facing L-shaped hooks 3112 a may beat a maximum. The combination structure may be able to be then expandedinto the expanded state, shown in FIGS. 31F-H, by retracting thecatheters with the proximally facing hooks 3112 b and corresponding endcap 3113 b towards the distally facing hooks 3112 a. The hourglassstructure 2910, valve support structure 2710, and support structure 3010may be fully radially deployed while the deployment structure 3210remains attached to the control catheter assembly. The combinationstructure may also be able to be recollapsed by manipulating thecatheters to move proximally facing hooks 3112 a and corresponding endcap 3113 a away from the distally facing hooks 3112 b and end cap 3113b. The catheters may be able to be retracted and lengthened by a surgeonat a location remote from the implant site. The ability to reversiblyexpand and collapse the combination structure may allow the device to bere-positioned by the surgeon. The surgeon may also use the controlcatheter assembly to rotate or retrieve the structure.

By manipulating the catheters such that the combination structure entersa fully expanded state, support structures 3010 may enter a lockedstate, described in more detail above, which may in turn cause thecombination structure to enter a locked state. In the locked state,inward radial pressure or axial pressure may not cause the combinationstructure to re-collapse. The combination structure may then be able tobe released from the control catheter assembly by sliding the end caps3113 off the hooks 3112, which may allow attachment rings 3111 to slipoff hooks 3112.

FIGS. 18A and 18B depict another embodiment of an articulated tubularstructure 1800, wherein at least one of the inner and outer struts 1802,1804 of the structure 1800 extend beyond the end articulations 1806,1808 of the struts 1802, 1804. As depicted in FIG. 18B, when thestructure 1800 is in a collapsed state, the struts 1802, 1804 may have agenerally linear configuration and comprising a slightly offset butgenerally longitudinal orientation (with respect to the longitudinalaxis of the structure 1800). In the expanded stated depicted in FIG.18A, the middle segments 1810, 1812 of the struts 1802, 1804 may assumean arcuate configuration (e.g. segment of a helix) with an acute anglerelative to the longitudinal axis of the structure 1800. As depicted inFIG. 18A (and also depicted in FIG. 1), in the expanded state, each ofthe outer struts 1816 may generally comprise the same angledorientation, relative to a perimeter of the structure, transverse thelongitudinal axis of the structure 1800, while each of the inner struts1814 may comprise the opposite angled orientation relative to theperimeter. The end segments 1814, 1816 of the struts 1802, 1804,however, may only be supported on one end at the end articulations 1806,1808, and therefore may comprise a generally linear configuration with atangential angle orientation relative to the adjacent middle segment1810, 1812. The end segments 1814, 1816, overall can provide thestructure 1800 with first and second perimeters that are larger than amiddle perimeter of the structure 1800, e.g. a parabolic shape. Therelative size differences between the first and second perimeters andthe middle perimeter may be affected by the length of the end segments1814, 1816 and the degree of expansion provided to the structure 1800,with relatively smaller size difference associated with smaller degreesof expansion and larger size differences (e.g. a more accentuatedparabolic shape vs. a more cylindrical shape) at larger degrees ofexpansion.

In another embodiment, illustrated in FIGS. 19A and 19B, the articulatedstructure 1900 may further comprise either inner 1902 and/or outer 1904bow struts. For illustrative purposes, only selected struts 1902, 1904are depicted on structure 1900, but a plurality of each type of bowstrut 1902, 1904 is contemplated, up to every available location on thestructure 1900. Each bow strut 1902, 1904 may comprise a first end 1906,1908 attached to an inner or outer strut 1910, 1912 at their respectivefirst ends 1914, 1916, and a second end 1918, 1920 attached to adifferent inner or outer strut 1922, 1924 at their respective oppositeends 1926, 1928. Typically, but not always, the different inner or outerstrut 1922, 1924 may be immediately or directed adjacent to the originalstrut 1910, 1912. Alternatively, instead of being attached at theopposite ends 1926, 1928 of the different strut 1922, 1924, the bowstruts may be attached to a middle position or a middle articulation ofthe struts 1922, 1924 (including but not limited to any of the middlearticulations of the multi-level articulated structure 2000 in FIG. 20,discussed below). As shown in FIG. 19B, the exemplary outer strut 1904may comprise a generally linear configuration when the structure 1900 isin a collapsed state, but in the expanded state depicted in FIG. 19A,the first end 1906, 1908 and second ends 1918, 1920 of the bow struts1902, 1904 come closer together, causing the bow struts 1902, 1904 tobow radially inward or outward, respectively. In some variations, thebow struts 1902, 1904 may be used to circumferentially retain otherstructures (not shown) between the inner bow struts 1902, 1904 and theprimary struts 1910, 1912, 1922, 1924. In one example, the otherstructure may comprise a tubular balloon, resilient seal, skirt, orelongate therapy delivery mechanism (e.g. electrodes, drug elution ordrug infusion, etc.).

FIG. 20 depicts another example of an articulated structure comprisingtubular articulated structure 2000 comprising longer struts 2002, 2004with more than one middle articulation 2006, 2008, 2010, in addition totheir end articulations 2012, 2014. With these additional features, thestruts 2002, 2004 may be arranged to provide two or more sets of cells2016, 2018, 2020 aligned along different perimeters 2022, 2024, 2026. Inaddition, to providing longer structures 2000, is was surprisinglydiscovered that the use of longer struts 2002, 2004 wherein at least twosets of cells 2016, 2018 are formed, the structure 2000 may be capableof self-expansion without additional mechanisms or forces acting on thestruts 2002, 2004 of the structure 2000. Although not wishing to bebound by the hypothesis, it is believed that this intrinsicself-expansion property of structure 2000 may be the result of greatertotal degree of curvature in the struts 2002, 2004 when in the collapsedstate, which results in greater stress and strain acting on the struts2002, 2004 that sufficient high that then can overcome resistance of thecollapsed state to relatively straighten to the expanded state, reducingits potential energy. Even more surprising, it was found thatembodiments of structure wherein the struts comprise two middlearticulations and two sets of aligned cells (one each less than theembodiment depicted in FIG. 20), the structure may have an intrinsicallystable collapsed state wherein the net frictional forces resistingexpansion exceed expansion forces of the struts, but if the structure isslightly expanded from the collapsed state to a point where the netfrictional forces of the structure are relatively lower (e.g. lessoverlapping surface area between the inner and outer struts), thestructure may still have at least some self-expansion ability. Incontrast, the embodiment depicted in FIGS. 1 and 3 may be configured tobe inherently stable at any configuration it is placed in, e.g. fullcollapse, partial collapse/expansion, and full expansion.

FIG. 21 schematically depicts another embodiment of an articulatedstructure 2100 comprising a set of radial struts 2102 with outer ends2104 coupled to the inner and/or outer struts 2106 and inner ends 2106coupled to the other inner ends 2106. Although FIG. 21 only depicts oneset of radial struts located at one end of the structure 2100, in otherembodiments, a second set of struts may be provided at the other end ofthe structure. The radial struts 2102 may or may not impart a radialexpansion force to the inner and/or outer struts 2106, depending upontheir configuration. In FIG. 22A, wherein the inner ends 2106 arerigidly affixed together, a greater expansion force may be imparted asthe inner ends 2106 attempt to straighten. Although the ends 2106 inFIG. 22A are depicted with apertures 2108 on their ends 2106 that arealigned, of course, the ends 2106 may be rigidly affixed togetherwithout apertures or without aligned apertures. In contrast, in FIG.22B, the loosely affixed ends 2106, performed by using a flexible orrigid loop or ring 2110 at their apertures 2108, may permit at leastsome tilting, pivoting or stress-relieving so that the radial struts donot impart any significant expansion force.

In some embodiments, a structure comprising two sets of radial strutsmay be used to perform radiofrequency or heater probe ablation oftissue. In further embodiments, the structure may be configured toprovide circumferential ablation of tissue in a cavity or tubular bodystructure. Depending upon the size of the structure and the degree ofradial expansion or resistance to radial collapse, the ablationstructure may be selected to ablate the opening of a cavity or lumen,while resisting significant entry into the cavity or lumen by resistingcollapse via the intrinsic mechanical properties of the inner and outerlumens, and/or the radial struts. Such an ablation device may be used,for example, for ablation about the pulmonary vein for treatment ofcardiac arrhythmias, or for ablation about the renal artery fortreatment of hypertension.

Structures comprising one or two sets of radial struts may be deployedusing any of a variety of mechanisms. In FIG. 23, for example, each setof radial struts 2302 and 2304 may articulate with separate deploymentstructures 2306 and 2308, which, depending upon whether the deploymentstructures 2306 and 2308 are flexible or rigid, may be configured todeployed by pulling and/or pushing of the deployment structure 2306 and2308. In other examples, such as the structure 2400 depicted in FIG. 24,both sets of radial struts 2402 and 2404 may be attached to a commondeployment structure or assembly 2406, where at least one or both of theattachments of the strut sets 2402 and 204 may be displacedlongitudinally to effectuate expansion and/or collapse of the structure2400.

Particular embodiments of the invention offer distinct advantages overthe prior art, including in their structure and applications. Whilecertain advantages are summarized below, the summary is not necessarilya complete list as there may be additional advantages.

The device may allow the user to advert the serious complications thatcan occur during percutaneous heart valve implantation. Because thedevice may be configured to be retrievable and re-positionable duringimplantation into the body, the surgeon may be able to avoid seriouscomplications due to valve mal-positioning or migration duringimplantation. Examples of these complications include occlusion of thecoronary arteries, massive paravalvular leakage, or arrhythmias.

The device may also decrease vascular access complications because ofthe device's narrow insertion profile. The device's profile may be low,in part, due to its unique geometry, which may allow neighboring strutsin the stent to overlap during stent compression. The device's lowprofile may be further augmented by eliminating the necessity for aballoon or a sheath. In some embodiments, however, the device may beplaced within a sheath during insertion. The device's narrow profileoffers the advantage of widening the vascular access route options inpatients. For instance, the device may enable the delivery of theprosthetic valve through an artery in the leg in a patient whom wouldhave previously been committed to a more invasive approach through thechest wall. The device may therefore decrease complications associatedwith the use of large profile devices in patients with poor vascularaccess.

The tissue valve embodiments can offer improved durability by allowingfor attachment of the leaflets to flexible commissural posts. Theflexible posts may allow dissipation of the stress and strain imposed onthe leaflet by the cardiac cycle. The use of multi-ply struts may enablethe leaflets to be sandwiched in between the struts, which mayre-enforce the leaflet attachments and prevents tearing of sutures andprovide a significantly simplified approach for leaflet attachment. Thevalve may further assume a desirable leaflet morphology, which mayfurther reduce the stress and strain on leaflets. Namely, the angledleaflet attachment to the stent may be similar to the native humanaortic valve's inter-leaflet trigone pattern. These properties maysignificantly improve the longevity of percutaneous heart valvereplacement therapies. In addition, in comparison to Nitinol frames, thesupport structure may have more forceful expansion and higher hoopstrength, and may be more fatigue resistant while collapsing moreeasily. Moreover, it may not require cooling or warning to cause shapechanges.

The device could reduce or eliminate arrhthymia complications due to theincremental expansion or compression of the stent. The stent can employa screw mechanism for deployment, which enables the stent to self-lockor un-lock at all radii. This may enable more controlled deployment andthe potential for individualizing the expansion or compression of thedevice in each patient. Because the expansion or compression of thedevice may be configured to be reversible at any stage during theprocedure, the surgeon may be able to easily reverse the expansion ofthe device to relieve an arrhythmia. In addition, if an arrhythmia isdetected during implantation, the device may be able to be repositionedto further eliminate the problem.

The device may reduce or eliminate paravalvular leak due to the device'sability to be accurately positioned, and re-positioned, if necessary.That may considerably decrease the occurrence and severity ofparavalular leaks. The device may also reduce or eliminate paravalvularleak due to the ability to retain a dynamic seal.

The device may eliminate balloon-related complications. The screwmechanism of deployment exploits the mechanical advantage of a screw.This may provide for forceful dilation of the stent. The lever armscreated by the pivoting of the struts in the scissor linkage of thestent may transmit a further expansion force to the stent. The stent maybe expanded without the need for a balloon. In addition, the device mayhave the ability to be forcefully dilated, which may reduce or eliminatethe need for pre- or postballooning during the implantation procedure inpatients.

The device may have more predictable and precise positioning in the bodybecause the difference between the height of the stent in the compressedand expanded position may be small. This “reduced foreshortening” mayhelp the surgeon to position the device in the desirable location in thebody. The ability to re-position the device in the body may furtherconfer the ability to precisely position the device in each individual.

In addition to the mechanical advantages, the device may enable a widerpopulation of patients to be treated by a less invasive means for valvereplacement. For example, the device may enable patients withco-morbidities, who are not candidates for open chest surgical valvereplacement, to be offered a treatment option. The device's ability toassume a narrow profile may also enable patients who were previouslydenied treatment due to poor vascular access (e.g. tortuous, calcified,or small arteries), to be offered a treatment option. The durability ofthe valve may expand the use of less-invasive procedures to thepopulation of otherwise healthy patients, who would otherwise becandidates for open chest surgical valve replacement. The device'sability to be forcefully expanded, or assume hourglass, or conicalshapes, potentially expands the device application to the treatment ofpatients diagnosed with aortic insufficiency, as well as aorticstenosis.

The device can also provide a less invasive treatment to patients withdegenerative prosthesis from a prior implant, by providing for a“valve-in-valve” procedure. The device could be accurately positionedinside the failing valve, without removing the patient's degenerativeprosthesis. It could help the patient by providing a functional valvereplacement, without a “re-do” operation and its associated risks.

While this invention has been particularly shown and described withreferences to particular embodiments, it will be understood by thoseskilled in the art that various changes in form and details may be madeto the embodiments without departing from the scope of the inventionencompassed by the appended claims. For the methods disclosed herein,the steps need not be performed sequentially. Each of the featuresdepicted in each embodiment herein in may be adapted for use in otherembodiments herein.

I claim:
 1. A biocompatible articulated support structure, comprising a tubular support body with a proximal opening, a distal opening, and a lumen and a longitudinal axis between the proximal and distal openings; wherein the tubular support body comprises a plurality of discrete struts coupled by a plurality of rotatable hinge joints, each rotatable hinge joint comprising an axis of rotation with a radial orientation; wherein the plurality of rotatable hinge joints comprise: a set of proximal rotatable hinge joints configured to reside in a proximal plane with the proximal opening; a set of distal rotatable hinge joints configured to reside in a distal plane with the distal opening; a first set of middle rotatable hinge joints, located between the proximal plane and the distal plane; and at least one commissural point hinge joint distal to the distal plane; wherein the plurality of discrete struts and the rotatable hinge joints therebetween intrinsically provide a self-expansion force; and wherein the plurality of discrete struts comprise a plurality of inner struts and a plurality of outer struts.
 2. The biocompatible articulated support structure of claim 1, wherein each of the at least one commissural point hinge joint is linked by at least two of the plurality of discrete struts to two commissural base hinge joints.
 3. The biocompatible articulated support structure of claim 2, wherein the two commissural base hinge joints are located at or proximal to the distal plane.
 4. The biocompatible articulated support structure of claim 1, wherein the first set of middle rotatable hinge joints, when the tubular support body is in an expanded state, are located closer to the proximal plane than the distal plane.
 5. The biocompatible articulated support structure of claim 1, wherein the plurality of inner struts comprises at least one commissural strut, and the plurality of outer struts comprises at least one commissural strut.
 6. The biocompatible articulated support structure of claim 1, wherein when the tubular support body is in an expanded state, the average angle of the at least one commissural point hinge joint is less than the average angle of the set of distal rotatable hinge joints.
 7. The biocompatible articulated support structure of claim 1, wherein when the tubular support body is in an expanded state, a distance between the at least one commissural point hinge joint and the distal plane is at least 20% of a longitudinal distance between the proximal and distal planes.
 8. The biocompatible articulated support structure of claim 1, further comprising an expandable hourglass securing body comprising a proximal opening, and a distal opening, with a lumen and a longitudinal axis between the proximal and distal openings, and wherein the tubular support body is configured to reside within the lumen of the expandable hourglass securing body.
 9. The biocompatible articulated support structure of claim 8, wherein the expandable hourglass securing body comprises a distal tapered section, a proximal tapered section, and a narrow section therebetween, and wherein the tubular support body is secured to the narrow section.
 10. The biocompatible articulated support structure of claim 9, wherein the expandable hourglass securing body comprises a plurality of discrete non-linear struts interconnected by rotatable hinge joints, each rotatable hinge joint comprising an axis of rotation with a radial orientation.
 11. The biocompatible articulated support structure of claim 9, further comprising at least one locking ring secured to at least one of the distal tapered section and the proximal tapered section.
 12. The biocompatible articulated support structure of claim 11, wherein the at least one locking ring is located within the lumen of the expandable hourglass securing body.
 13. The biocompatible articulated support structure of claim 11, wherein the at least one locking ring comprises a plurality of inner struts and a plurality of outer struts interconnected by rotatable hinge joints, each rotatable hinge joint comprising an axis of rotation with a radial orientation. 